Cygwin comes with a number of command-line utilities that are used to manage the UNIX emulation portion of the Cygwin environment. While many of these reflect their UNIX counterparts, each was written specifically for Cygwin. You may use the long or short option names interchangeably; for example, --help and -h function identically. All of the Cygwin command-line utilities support the --help and --version options. Usage: cygcheck PROGRAM [ -v ] [ -h ] cygcheck -c [ PACKAGE ... ] [ -d ] cygcheck -s [ -r ] [ -v ] [ -h ] cygcheck -k cygcheck -f FILE [ FILE ... ] cygcheck -l [ PACKAGE ... ] cygcheck -p REGEXP List system information, check installed packages, or query package database. At least one command option or a PROGRAM is required, as shown above. PROGRAM list library (DLL) dependencies of PROGRAM -c, --check-setup show installed version of PACKAGE and verify integrity (or for all installed packages if none specified) -d, --dump-only just list packages, do not verify (with -c) -s, --sysinfo produce diagnostic system information (implies -c -d) -r, --registry also scan registry for Cygwin settings (with -s) -k, --keycheck perform a keyboard check session (must be run from a plain console only, not from a pty/rxvt/xterm) -f, --find-package find the package to which FILE belongs -l, --list-package list contents of PACKAGE (or all packages if none given) -p, --package-query search for REGEXP in the entire cygwin.com package repository (requires internet connectivity) -v, --verbose produce more verbose output -h, --help annotate output with explanatory comments when given with another command, otherwise print this help -V, --version print the version of cygcheck and exit Note: -c, -f, and -l only report on packages that are currently installed. To search all official Cygwin packages use -p instead. The -p REGEXP matches package names, descriptions, and names of files/paths within all packages. The cygcheck program is a diagnostic utility for dealing with Cygwin programs. If you are familiar with dpkg or rpm, cygcheck is similar in many ways. (The major difference is that setup.exe handles installing and uninstalling packages; see for more information.) The -c option checks the version and status of installed Cygwin packages. If you specify one or more package names, cygcheck will limit its output to those packages, or with no arguments it lists all packages. A package will be marked Incomplete if files originally installed are no longer present. The best thing to do in that situation is reinstall the package with setup.exe. To see which files are missing, use the -v option. If you do not need to know the status of each package and want cygcheck to run faster, add the -d option and cygcheck will only output the name and version for each package. If you list one or more programs on the command line, cygcheck will diagnose the runtime environment of that program or programs, providing the names of DLL files on which the program depends. If you specify the -s option, cygcheck will give general system information. If you list one or more programs on the command line and specify -s, cygcheck will report on both. The -f option helps you to track down which package a file came from, and -l lists all files in a package. For example, to find out about /usr/bin/less and its package: $ cygcheck -f /usr/bin/less less-381-1 $ cygcheck -l less /usr/bin/less.exe /usr/bin/lessecho.exe /usr/bin/lesskey.exe /usr/man/man1/less.1 /usr/man/man1/lesskey.1 The -h option prints additional helpful messages in the report, at the beginning of each section. It also adds table column headings. While this is useful information, it also adds some to the size of the report, so if you want a compact report or if you know what everything is already, just leave this out. The -v option causes the output to be more verbose. What this means is that additional information will be reported which is usually not interesting, such as the internal version numbers of DLLs, additional information about recursive DLL usage, and if a file in one directory in the PATH also occurs in other directories on the PATH. The -r option causes cygcheck to search your registry for information that is relevent to Cygwin programs. These registry entries are the ones that have "Cygwin" in the name. If you are paranoid about privacy, you may remove information from this report, but please keep in mind that doing so makes it harder to diagnose your problems. In contrast to the other options that search the packages that are installed on your local system, the -p option can be used to search the entire official Cygwin package repository. It takes as argument a Perl-compatible regular expression which is used to match package names, package descriptions, and path/filenames of the contents of packages. This feature requires an active internet connection, since it must query the cygwin.com web site. In fact, it is equalivant to the search that is available on the Cygwin package listing page. For example, perhaps you are getting an error because you are missing a certain DLL and you want to know which package includes that file: $ cygcheck -p 'cygintl-2\.dll' Found 1 matches for 'cygintl-2\.dll'. libintl2-0.12.1-3 GNU Internationalization runtime library $ cygcheck -p 'libexpat.*\.a' Found 2 matches for 'libexpat.*\.a'. expat-1.95.7-1 XML parser library written in C expat-1.95.8-1 XML parser library written in C $ cygcheck -p '/ls\.exe' Found 2 matches for '/ls\.exe'. coreutils-5.2.1-5 GNU core utilities (includes fileutils, sh-utils and textutils) coreutils-5.3.0-6 GNU core utilities (includes fileutils, sh-utils and textutils) Note that this option takes a regular expression, not a glob or wildcard. This means that you need to use .* if you want something similar to the wildcard * commonly used in filename globbing. Similarly, to match the period character you should use \. since the . character in a regexp is a metacharacter that will match any character. Also be aware that the characters such as \ and * are shell metacharacters, so they must be either escaped or quoted, as in the example above. The third example above illustrates that if you want to match a whole filename, you should include the / path seperator. In the given example this ensures that filenames that happen to end in ls.exe such as ncftpls.exe are not shown. Note that this use does not mean "look for packages with ls in the root directory," since the / can match anywhere in the path. It's just there to anchor the match so that it matches a full filename. By default the matching is case-sensitive. To get a case insensitive match, begin your regexp with (?i) which is a PCRE-specific feature. For complete documentation on Perl-compatible regular expression syntax and options, read the perlre manpage, or one of many websites such as perldoc.com that document the Perl language. The cygcheck program should be used to send information about your system for troubleshooting when requested. When asked to run this command save the output so that you can email it, for example: $ cygcheck -s -v -r -h > cygcheck_output.txt Usage: cygpath (-d|-m|-u|-w|-t TYPE) [-f FILE] [OPTION]... NAME... cygpath [-c HANDLE] cygpath [-ADHOPSW] cygpath [-F ID] Convert Unix and Windows format paths, or output system path information Output type options: -d, --dos print DOS (short) form of NAMEs (C:\PROGRA~1\) -m, --mixed like --windows, but with regular slashes (C:/WINNT) -M, --mode report on mode of file (currently binmode or textmode) -u, --unix (default) print Unix form of NAMEs (/cygdrive/c/winnt) -w, --windows print Windows form of NAMEs (C:\WINNT) -t, --type TYPE print TYPE form: 'dos', 'mixed', 'unix', or 'windows' Path conversion options: -a, --absolute output absolute path -l, --long-name print Windows long form of NAMEs (with -w, -m only) -p, --path NAME is a PATH list (i.e., '/bin:/usr/bin') -s, --short-name print DOS (short) form of NAMEs (with -w, -m only) -C, --codepage CP print DOS, Windows, or mixed pathname in Windows codepage CP. CP can be a numeric codepage identifier, or one of the reserved words ANSI, OEM, or UTF8. If this option is missing, cygpath defaults to the character set defined by the current locale. System information: -A, --allusers use `All Users' instead of current user for -D, -P -D, --desktop output `Desktop' directory and exit -H, --homeroot output `Profiles' directory (home root) and exit -O, --mydocs output `My Documents' directory and exit -P, --smprograms output Start Menu `Programs' directory and exit -S, --sysdir output system directory and exit -W, --windir output `Windows' directory and exit -F, --folder ID output special folder with numeric ID and exit Other options: -f, --file FILE read FILE for input; use - to read from STDIN -o, --option read options from FILE as well (for use with --file) -c, --close HANDLE close HANDLE (for use in captured process) -i, --ignore ignore missing argument -h, --help output usage information and exit -v, --version output version information and exit The cygpath program is a utility that converts Windows native filenames to Cygwin POSIX-style pathnames and vice versa. It can be used when a Cygwin program needs to pass a file name to a native Windows program, or expects to get a file name from a native Windows program. Alternatively, cygpath can output information about the location of important system directories in either format. The -u and -w options indicate whether you want a conversion to UNIX (POSIX) format (-u) or to Windows format (-w). Use the -d to get DOS-style (8.3) file and path names. The -m option will output Windows-style format but with forward slashes instead of backslashes. This option is especially useful in shell scripts, which use backslashes as an escape character. In combination with the -w option, you can use the -l and -s options to use normal (long) or DOS-style (short) form. The -d option is identical to -w and -s together. The -C option allows to specify a Windows codepage to print DOS and Windows paths created with one of the -d, -m, or -w options. The default is to use the character set of the current locale defined by one of the internationalization environment variables LC_ALL, LC_CTYPE, or LANG, see . This is sometimes not sufficent for interaction with native Windows tools, which might expect native, non-ASCII characters in a specific Windows codepage. Console tools, for instance, might expect pathnames in the current OEM codepage, while graphical tools like Windows Explorer might expect pathnames in the current ANSI codepage. The -C option takes a single parameter: ANSI, to specify the current ANSI codepage OEM, to specify the current OEM (console) codepage UTF8, to specify UTF-8. A numerical, decimal codepage number, for instance 936 for GBK, 28593 for ISO-8859-3, etc. A full list of supported codepages is listed on the Microsoft MSDN page Code Page Identifiers. A codepage of 0 is the same as if the -C hasn't been specified at all. The -p option means that you want to convert a path-style string rather than a single filename. For example, the PATH environment variable is semicolon-delimited in Windows, but colon-delimited in UNIX. By giving -p you are instructing cygpath to convert between these formats. The -i option supresses the print out of the usage message if no filename argument was given. It can be used in make file rules converting variables that may be omitted to a proper format. Note that cygpath output may contain spaces (C:\Program Files) so should be enclosed in quotes. The capital options -D, -H, -P, -S, and -W output directories used by Windows that are not the same on all systems, for example -S might output C:\WINNT\system32 or C:\Windows\System32. The -H shows the Windows profiles directory that can be used as root of home. The -A option forces use of the "All Users" directories instead of the current user for the -D, -O and -P options. The -F outputs other special folders specified by their internal numeric code (decimal or 0xhex). For valid codes and symbolic names, see the CSIDL_* definitions in the include file /usr/include/w32api/shlobj.h from package w32api. The current valid range of codes for folders is 0 (Desktop) to 59 (CDBurn area). By default the output is in UNIX (POSIX) format; use the -w or -d options to get other formats. Usage: dumper [OPTION] FILENAME WIN32PID Dump core from WIN32PID to FILENAME.core -d, --verbose be verbose while dumping -h, --help output help information and exit -q, --quiet be quiet while dumping (default) -v, --version output version information and exit The dumper utility can be used to create a core dump of running Windows process. This core dump can be later loaded to gdb and analyzed. One common way to use dumper is to plug it into cygwin's Just-In-Time debugging facility by adding error_start=x:\path\to\dumper.exe to the CYGWIN environment variable. Please note that x:\path\to\dumper.exe is Windows-style and not cygwin path. If error_start is set this way, then dumper will be started whenever some program encounters a fatal error. dumper can be also be started from the command line to create a core dump of any running process. Unfortunately, because of a Windows API limitation, when a core dump is created and dumper exits, the target process is terminated too. To save space in the core dump, dumper doesn't write those portions of target process' memory space that are loaded from executable and dll files and are unchangeable, such as program code and debug info. Instead, dumper saves paths to files which contain that data. When a core dump is loaded into gdb, it uses these paths to load appropriate files. That means that if you create a core dump on one machine and try to debug it on another, you'll need to place identical copies of the executable and dlls in the same directories as on the machine where the core dump was created. Usage: getfacl [-adn] FILE [FILE2...] Display file and directory access control lists (ACLs). -a, --all display the filename, the owner, the group, and the ACL of the file -d, --dir display the filename, the owner, the group, and the default ACL of the directory, if it exists -h, --help output usage information and exit -n, --noname display user and group IDs instead of names -v, --version output version information and exit When multiple files are specified on the command line, a blank line separates the ACLs for each file. For each argument that is a regular file, special file or directory, getfacl displays the owner, the group, and the ACL. For directories getfacl displays additionally the default ACL. With no options specified, getfacl displays the filename, the owner, the group, and both the ACL and the default ACL, if it exists. For more information on Cygwin and Windows ACLs, see in the Cygwin User's Guide. The format for ACL output is as follows: # file: filename # owner: name or uid # group: name or uid user::perm user:name or uid:perm group::perm group:name or gid:perm mask:perm other:perm default:user::perm default:user:name or uid:perm default:group::perm default:group:name or gid:perm default:mask:perm default:other:perm Usage: kill [-f] [-signal] [-s signal] pid1 [pid2 ...] kill -l [signal] Send signals to processes -f, --force force, using win32 interface if necessary -l, --list print a list of signal names -s, --signal send signal (use kill --list for a list) -h, --help output usage information and exit -v, --version output version information and exit The kill program allows you to send arbitrary signals to other Cygwin programs. The usual purpose is to end a running program from some other window when ^C won't work, but you can also send program-specified signals such as SIGUSR1 to trigger actions within the program, like enabling debugging or re-opening log files. Each program defines the signals they understand. You may need to specify the full path to use kill from within some shells, including bash, the default Cygwin shell. This is because bash defines a kill builtin function; see the bash man page under BUILTIN COMMANDS for more information. To make sure you are using the Cygwin version, try $ /bin/kill --version which should give the Cygwin kill version number and copyright information. Unless you specific the -f option, the "pid" values used by kill are the Cygwin pids, not the Windows pids. To get a list of running programs and their Cygwin pids, use the Cygwin ps program. ps -W will display all windows pids. The kill -l option prints the name of the given signal, or a list of all signal names if no signal is given. To send a specific signal, use the -signN option, either with a signal number or a signal name (minus the "SIG" part), as shown in these examples: $ kill 123 $ kill -1 123 $ kill -HUP 123 $ kill -f 123 Here is a list of available signals, their numbers, and some commentary on them, from the file <sys/signal.h>, which should be considered the official source of this information. SIGHUP 1 hangup SIGINT 2 interrupt SIGQUIT 3 quit SIGILL 4 illegal instruction (not reset when caught) SIGTRAP 5 trace trap (not reset when caught) SIGABRT 6 used by abort SIGEMT 7 EMT instruction SIGFPE 8 floating point exception SIGKILL 9 kill (cannot be caught or ignored) SIGBUS 10 bus error SIGSEGV 11 segmentation violation SIGSYS 12 bad argument to system call SIGPIPE 13 write on a pipe with no one to read it SIGALRM 14 alarm clock SIGTERM 15 software termination signal from kill SIGURG 16 urgent condition on IO channel SIGSTOP 17 sendable stop signal not from tty SIGTSTP 18 stop signal from tty SIGCONT 19 continue a stopped process SIGCHLD 20 to parent on child stop or exit SIGTTIN 21 to readers pgrp upon background tty read SIGTTOU 22 like TTIN for output if (tp->t_local&LTOSTOP) SIGPOLL 23 System V name for SIGIO SIGXCPU 24 exceeded CPU time limit SIGXFSZ 25 exceeded file size limit SIGVTALRM 26 virtual time alarm SIGPROF 27 profiling time alarm SIGWINCH 28 window changed SIGLOST 29 resource lost (eg, record-lock lost) SIGUSR1 30 user defined signal 1 SIGUSR2 31 user defined signal 2 Usage: mkgroup [OPTION]... Print /etc/group file to stdout Options: -l,--local [machine[,offset]] print local groups with gid offset offset (from local machine if no machine specified) -L,--Local [machine[,offset]] ditto, but generate groupname with machine prefix -d,--domain [domain[,offset]] print domain groups with gid offset offset (from current domain if no domain specified) -D,--Domain [domain[,offset]] ditto, but generate groupname with machine prefix -c,--current print current group -C,--Current ditto, but generate groupname with machine or domain prefix -S,--separator char for -L, -D, -C use character char as domain\group separator in groupname instead of the default '\' -o,--id-offset offset change the default offset (10000) added to gids in domain or foreign server accounts. -g,--group groupname only return information for the specified group one of -l, -L, -d, -D must be specified, too -b,--no-builtin don't print BUILTIN groups -U,--unix grouplist additionally print UNIX groups when using -l or -L on a UNIX Samba server grouplist is a comma-separated list of groupnames or gid ranges (root,-25,50-100). (enumerating large ranges can take a long time!) -s,--no-sids (ignored) -u,--users (ignored) -h,--help print this message -v,--version print version information and exit Default is to print local groups on stand-alone machines, plus domain groups on domain controllers and domain member machines. The mkgroup program can be used to help configure Cygwin by creating a /etc/group file. Its use is essential to include Windows security information. The command is initially called by setup.exe to create a default /etc/group. This should be sufficient in most circumstances. However, especially when working in a multi-domain environment, you can use mkgroup manually to create a more complete /etc/group file for all domains. Especially when you have the same group name used on multiple machines or in multiple domains, you can use the -D, -L and -C options to create unique domain\group style groupnames. Note that this information is static. If you change the group information in your system, you'll need to regenerate the group file for it to have the new information. The -d/-D and -l/-L options allow you to specify where the information comes from, the local SAM of a machine or from the domain, or both. With the -d/-D options the program contacts a Domain Controller, which my be unreachable or have restricted access. Comma-separated from the machine or domain, you can specify an offset which is used as base added to the group's RID to compute the gid (offset + RID = gid). This allows you to create the same gids every time you re-run mkgroup. For very simple needs, an entry for the current user's group can be created by using the option -c or -C. If you want to use one of the -D, -L or -C options, but you don't like the backslash as domain/group separator, you can specify another separator using the -S option, for instance: $ mkgroup -C -S+ > /etc/group $ cat /etc/group DOMAIN+my_group:S-1-5-21-2913048732-1697188782-3448811101-1144:11144: The -o option allows for special cases (such as multiple domains) where the GIDs might match otherwise. The -g option only prints the information for one group. The -U option allows you to enumerate the standard UNIX groups on a Samba machine. It's used together with -l samba-server or -L samba-server. The normal UNIX groups are usually not enumerated, but they can show up as a group in ls -l output. Usage: mkpasswd [OPTIONS]... Print /etc/passwd file to stdout Options: -l,--local [machine[,offset]] print local user accounts with uid offset offset (from local machine if no machine specified) -L,--Local [machine[,offset]] ditto, but generate username with machine prefix -d,--domain [domain[,offset]] print domain accounts with uid offset offset (from current domain if no domain specified) -D,--Domain [domain[,offset]] ditto, but generate username with domain prefix -c,--current print current user -C,--Current ditto, but generate username with machine or domain prefix -S,--separator char for -L, -D, -C use character char as domain\user separator in username instead of the default '\' -o,--id-offset offset change the default offset (10000) added to uids in domain or foreign server accounts. -u,--username username only return information for the specified user one of -l, -L, -d, -D must be specified, too -p,--path-to-home path use specified path instead of user account home dir or /home prefix -m,--no-mount don't use mount points for home dir -U,--unix userlist additionally print UNIX users when using -l or -L\ on a UNIX Samba server userlist is a comma-separated list of usernames or uid ranges (root,-25,50-100). (enumerating large ranges can take a long time!) -s,--no-sids (ignored) -g,--local-groups (ignored) -h,--help displays this message -v,--version version information and exit Default is to print local accounts on stand-alone machines, domain accounts on domain controllers and domain member machines. The mkpasswd program can be used to help configure Cygwin by creating a /etc/passwd from your system information. Its use is essential to include Windows security information. However, the actual passwords are determined by Windows, not by the content of /etc/passwd. The command is initially called by setup.exe to create a default /etc/passwd. This should be sufficient in most circumstances. However, especially when working in a multi-domain environment, you can use mkpasswd manually to create a more complete /etc/passwd file for all domains. Especially when you have the same user name used on multiple machines or in multiple domains, you can use the -D, -L and -C options to create unique domain\user style usernames. Note that this information is static. If you change the user information in your system, you'll need to regenerate the passwd file for it to have the new information. The -d/-D and -l/-L options allow you to specify where the information comes from, the local machine or the domain (default or given), or both. With the -d/-D options the program contacts the Domain Controller, which may be unreachable or have restricted access. Comma-separated from the machine or domain, you can specify an offset which is used as base added to the user's RID to compute the uid (offset + RID = uid). This allows to create the same uids every time you re-run mkpasswd. An entry for the current user can be created by using the option -c or -C. If you want to use one of the -D, -L or -C options, but you don't like the backslash as domain/group separator, you can specify another separator using the -S option, similar to the mkgroup. The -o option allows for special cases (such as multiple domains) where the UIDs might match otherwise. The -m option bypasses the current mount table so that, for example, two users who have a Windows home directory of H: could mount them differently. For more information on SIDs, see in the Cygwin User's Guide. The -p option causes mkpasswd to use the specified prefix instead of the account home dir or /home/ . For example, this command: $ mkpasswd -l -p "$(cygpath -H)" > /etc/passwd would put local users' home directories in the Windows 'Profiles' directory. The -u option creates just an entry for the specified user. The -U option allows you to enumerate the standard UNIX users on a Samba machine. It's used together with -l samba-server or -L samba-server. The normal UNIX users are usually not enumerated, but they can show up as file owners in ls -l output. Usage: mount [OPTION] [<win32path> <posixpath>] mount -a mount <posixpath> Display information about mounted filesystems, or mount a filesystem -a, --all mount all filesystems mentioned in fstab -c, --change-cygdrive-prefix change the cygdrive path prefix to <posixpath> -f, --force force mount, don't warn about missing mount point directories -h, --help output usage information and exit -m, --mount-entries write fstab entries to replicate mount points and cygdrive prefixes -o, --options X[,X...] specify mount options -p, --show-cygdrive-prefix show user and/or system cygdrive path prefix -v, --version output version information and exit The mount program is used to map your drives and shares onto Cygwin's simulated POSIX directory tree, much like as is done by mount commands on typical UNIX systems. However, in contrast to mount points given in /etc/fstab, mount points created or changed with mount are not persistent. They disappear immediately after the last process of the current user exited. Please see for more information on the concepts behind the Cygwin POSIX file system and strategies for using mounts. To remove mounts temporarily, use umount If you just type mount with no parameters, it will display the current mount table for you. $ mount c:\cygwin\bin on /usr/bin type ntfs (binary) c:\cygwin\lib on /usr/lib type ntfs (binary) c:\cygwin on / type ntfs (binary) c: on /c type ntfs (binary,user,noumount) d: on /d type fat (binary,user,noumount) In this example, c:\cygwin is the POSIX root and D drive is mapped to /d. Note that in this case, the root mount is a system-wide mount point that is visible to all users running Cygwin programs, whereas the /d mount is only visible to the current user. The mount utility is also the mechanism for adding new mounts to the mount table. The following example demonstrates how to mount the directory //pollux/home/joe/data to /data for the duration of the current session. $ ls /data ls: /data: No such file or directory $ mount //pollux/home/joe/data /data mount: warning - /data does not exist! $ mount //pollux/home/joe/data on /data type smbfs (binary) c:/cygwin/bin on /usr/bin type ntfs (binary) c:/cygwin/lib on /usr/lib type ntfs (binary) c:/cygwin on / type ntfs (binary) c: on /c type ntfs (binary,user,noumount) d: on /d type fat (binary,user,noumount) A given POSIX path may only exist once in the mount table. Attempts to replace the mount will fail with a busy error. The -f (force) option causes the old mount to be silently replaced with the new one, provided the old mount point was a user mount point. It's not valid to replace system-wide mount points. Additionally, the -f option will silence warnings about the non-existence of directories at the Win32 path location. The -o option is the method via which various options about the mount point may be recorded. The following options are available (note that most of the options are duplicates of other mount flags): acl - Use the filesystem's access control lists (ACLs) to implement real POSIX permissions (default). binary - Files default to binary mode (default). cygexec - Treat all files below mount point as cygwin executables. exec - Treat all files below mount point as executable. noacl - Ignore ACLs and fake POSIX permissions. nosuid - No suid files are allowed (currently unimplemented) notexec - Treat all files below mount point as not executable. override - Override immutable mount points. posix=0 - Switch off case sensitivity for paths under this mount point. posix=1 - Switch on case sensitivity for paths under this mount point (default). text - Files default to CRLF text mode line endings. For a more complete description of the mount options and the /etc/fstab file, see . Note that all mount points added with mount are user mount points. System mount points can only be specified in the /etc/fstab file. If you added mount points to /etc/fstab or your /etc/fstab.d/<username> file, you can add these mount points to your current user session using the -a/--all option, or by specifing the posix path alone on the command line. As an example, consider you added a mount point with the POSIX path /my/mount. You can add this mount point with either one of the following two commands to your current user session. $ mount /my/mount $ mount -a The first command just adds the /my/mount mount point to your current session, the mount -a adds all new mount points to your user session. If you change a mount point to point to another native path, or if you changed the flags of a mount point, you have to umount the mount point first, before you can add it again. Please note that all such added mount points are added as user mount points, and that the rule that system mount points can't be removed or replaced in a running session still applies. The -m option causes the mount utility to output the current mount table in a series of fstab entries. You can save this output as a backup when experimenting with the mount table. Copy the output to /etc/fstab to restore the old state. It also makes moving your settings to a different machine much easier. Whenever Cygwin cannot use any of the existing mounts to convert from a particular Win32 path to a POSIX one, Cygwin will, instead, convert to a POSIX path using a default mount point: /cygdrive. For example, if Cygwin accesses z:\foo and the z drive is not currently in the mount table, then z:\ will be accessible as /cygdrive/z. The mount utility can be used to change this default automount prefix through the use of the "--change-cygdrive-prefix" option. In the following example, we will set the automount prefix to /mnt: $ mount --change-cygdrive-prefix /mnt Note that the cygdrive prefix can be set both per-user and system-wide, and that as with all mounts, a user-specific mount takes precedence over the system-wide setting. The mount utility creates system-wide mounts by default if you do not specify a type. You can always see the user and system cygdrive prefixes with the -p option. Using the --options flag with --change-cygdrive-prefix makes all new automounted filesystems default to this set of options. For instance (using the short form of the command line flags) $ mount -c /mnt -o binary,noacl Limitations: there is a hard-coded limit of 30 mount points. Also, although you can mount to pathnames that do not start with "/", there is no way to make use of such mount points. Normally the POSIX mount point in Cygwin is an existing empty directory, as in standard UNIX. If this is the case, or if there is a place-holder for the mount point (such as a file, a symbolic link pointing anywhere, or a non-empty directory), you will get the expected behavior. Files present in a mount point directory before the mount become invisible to Cygwin programs. It is sometimes desirable to mount to a non-existent directory, for example to avoid cluttering the root directory with names such as a, b, c pointing to disks. Although mount will give you a warning, most everything will work properly when you refer to the mount point explicitly. Some strange effects can occur however. For example if your current working directory is /dir, say, and /dir/mtpt is a mount point, then mtpt will not show up in an ls or echo * command and find . will not find mtpt. Usage: passwd [OPTION] [USER] Change USER's password or password attributes. User operations: -l, --lock lock USER's account. -u, --unlock unlock USER's account. -c, --cannot-change USER can't change password. -C, --can-change USER can change password. -e, --never-expires USER's password never expires. -E, --expires USER's password expires according to system's password aging rule. -p, --pwd-not-required no password required for USER. -P, --pwd-required password is required for USER. -R, --reg-store-pwd enter password to store it in the registry for later usage by services to be able to switch to this user context with network credentials. System operations: -i, --inactive NUM set NUM of days before inactive accounts are disabled (inactive accounts are those with expired passwords). -n, --minage DAYS set system minimum password age to DAYS days. -x, --maxage DAYS set system maximum password age to DAYS days. -L, --length LEN set system minimum password length to LEN. Other options: -d, --logonserver SERVER connect to SERVER (e.g. domain controller). Default server is the local system, unless changing the current user, in which case the default is the content of $LOGONSERVER. -S, --status display password status for USER (locked, expired, etc.) plus global system password settings. -h, --help output usage information and exit. -v, --version output version information and exit. If no option is given, change USER's password. If no user name is given, operate on current user. System operations must not be mixed with user operations. Don't specify a USER when triggering a system operation. Don't specify a user or any other option together with the -R option. Non-Admin users can only store their password if cygserver is running. Note that storing even obfuscated passwords in the registry is not overly secure. Use this feature only if the machine is adequately locked down. Don't use this feature if you don't need network access within a remote session. You can delete your stored password by using `passwd -R' and specifying an empty password. passwd changes passwords for user accounts. A normal user may only change the password for their own account, but administrators may change passwords on any account. passwd also changes account information, such as password expiry dates and intervals. For password changes, the user is first prompted for their old password, if one is present. This password is then encrypted and compared against the stored password. The user has only one chance to enter the correct password. The administrators are permitted to bypass this step so that forgotten passwords may be changed. The user is then prompted for a replacement password. passwd will prompt twice for this replacement and compare the second entry against the first. Both entries are required to match in order for the password to be changed. After the password has been entered, password aging information is checked to see if the user is permitted to change their password at this time. If not, passwd refuses to change the password and exits. To get current password status information, use the -S option. Administrators can use passwd to perform several account maintenance functions (users may perform some of these functions on their own accounts). Accounts may be locked with the -l flag and unlocked with the -u flag. Similarly, -c disables a user's ability to change passwords, and -C allows a user to change passwords. For password expiry, the -e option disables expiration, while the -E option causes the password to expire according to the system's normal aging rules. Use -p to disable the password requirement for a user, or -P to require a password. Administrators can also use passwd to change system-wide password expiry and length requirements with the -i, -n, -x, and -L options. The -i option is used to disable an account after the password has been expired for a number of days. After a user account has had an expired password for NUM days, the user may no longer sign on to the account. The -n option is used to set the minimum number of days before a password may be changed. The user will not be permitted to change the password until MINDAYS days have elapsed. The -x option is used to set the maximum number of days a password remains valid. After MAXDAYS days, the password is required to be changed. Allowed values for the above options are 0 to 999. The -L option sets the minimum length of allowed passwords for users who don't belong to the administrators group to LEN characters. Allowed values for the minimum password length are 0 to 14. In any of the above cases, a value of 0 means `no restrictions'. All operations affecting the current user are by default run against the logon server of the current user (taken from the environment variable LOGONSERVER. When password or account information of other users should be changed, the default server is the local system. To change a user account on a remote machine, use the -d option to specify the machine to run the command against. Note that the current user must be a valid member of the administrators group on the remote machine to perform such actions. Users can use the passwd -R to enter a password which then gets stored in a special area of the registry on the local system, which is also used by Windows to store passwords of accounts running Windows services. When a privileged Cygwin application calls the set{e}uid(user_id) system call, Cygwin checks if a password for that user has been stored in this registry area. If so, it uses this password to switch to this user account using that password. This allows you to logon through, for instance, ssh with public key authentication and get a full qualified user token with all credentials for network access. However, the method has some drawbacks security-wise. This is explained in more detail in . Please note that storing passwords in that registry area is a privileged operation which only administrative accounts are allowed to do. If normal, non-admin users should be allowed to enter their passwords using passwd -R, it's required to run cygserver as a service under the LocalSystem account before running passwd -R. This only affects storing passwords. Using passwords in privileged processes does not require cygserver to run. Limitations: Users may not be able to change their password on some systems. Usage: ps [-aefls] [-u UID] Report process status -a, --all show processes of all users -e, --everyone show processes of all users -f, --full show process uids, ppids -h, --help output usage information and exit -l, --long show process uids, ppids, pgids, winpids -p, --process show information for specified PID -s, --summary show process summary -u, --user list processes owned by UID -v, --version output version information and exit -W, --windows show windows as well as cygwin processes With no options, ps outputs the long format by default The ps program gives the status of all the Cygwin processes running on the system (ps = "process status"). Due to the limitations of simulating a POSIX environment under Windows, there is little information to give. The PID column is the process ID you need to give to the kill command. The PPID is the parent process ID, and PGID is the process group ID. The WINPID column is the process ID displayed by NT's Task Manager program. The TTY column gives which pseudo-terminal a process is running on, or a '?' for services. The UID column shows which user owns each process. STIME is the time the process was started, and COMMAND gives the name of the program running. Listings may also have a status flag in column zero; S means stopped or suspended (in other words, in the background), I means waiting for input or interactive (foreground), and O means waiting to output. By default, ps will only show processes owned by the current user. With either the -a or -e option, all user's processes (and system processes) are listed. There are historical UNIX reasons for the synonomous options, which are functionally identical. The -f option outputs a "full" listing with usernames for UIDs. The -l option is the default display mode, showing a "long" listing with all the above columns. The other display option is -s, which outputs a shorter listing of just PID, TTY, STIME, and COMMAND. The -u option allows you to show only processes owned by a specific user. The -p option allows you to show information for only the process with the specified PID. The -W option causes ps show non-Cygwin Windows processes as well as Cygwin processes. The WINPID is also the PID, and they can be killed with the Cygwin kill command's -f option. Usage: regtool [OPTION] (add|check|get|list|remove|unset|load|unload|save) KEY View or edit the Win32 registry Actions: add KEY\SUBKEY add new SUBKEY check KEY exit 0 if KEY exists, 1 if not get KEY\VALUE prints VALUE to stdout list KEY list SUBKEYs and VALUEs remove KEY remove KEY set KEY\VALUE [data ...] set VALUE unset KEY\VALUE removes VALUE from KEY load KEY\SUBKEY PATH load hive from PATH into new SUBKEY unload KEY\SUBKEY unload hive and remove SUBKEY save KEY\SUBKEY PATH save SUBKEY into new hive PATH Options for 'list' Action: -k, --keys print only KEYs -l, --list print only VALUEs -p, --postfix like ls -p, appends '\' postfix to KEY names Options for 'get' Action: -b, --binary print REG_BINARY data as hex bytes Options for 'set' Action: -b, --binary set type to REG_BINARY (hex args or '-') -e, --expand-string set type to REG_EXPAND_SZ -i, --integer set type to REG_DWORD -m, --multi-string set type to REG_MULTI_SZ -s, --string set type to REG_SZ Options for 'set' and 'unset' Actions: -K<c>, --key-separator[=]<c> set key separator to <c> instead of '\' Other Options: -h, --help output usage information and exit -q, --quiet no error output, just nonzero return if KEY/VALUE missing -v, --verbose verbose output, including VALUE contents when applicable -w, --wow64 access 64 bit registry view (ignored on 32 bit Windows) -W, --wow32 access 32 bit registry view (ignored on 32 bit Windows) -V, --version output version information and exit KEY is in the format [host]\prefix\KEY\KEY\VALUE, where host is optional remote host in either \\hostname or hostname: format and prefix is any of: root HKCR HKEY_CLASSES_ROOT (local only) config HKCC HKEY_CURRENT_CONFIG (local only) user HKCU HKEY_CURRENT_USER (local only) machine HKLM HKEY_LOCAL_MACHINE users HKU HKEY_USERS You can use forward slash ('/') as a separator instead of backslash, in that case backslash is treated as escape character Example: regtool.exe get '\user\software\Microsoft\Clock\iFormat' The regtool program allows shell scripts to access and modify the Windows registry. Note that modifying the Windows registry is dangerous, and carelessness here can result in an unusable system. Be careful. The -v option means "verbose". For most commands, this causes additional or lengthier messages to be printed. Conversely, the -q option supresses error messages, so you can use the exit status of the program to detect if a key exists or not (for example). The -w option allows you to access the 64 bit view of the registry. Several subkeys exist in a 32 bit and a 64 bit version when running on Windows 64. Since Cygwin is running in 32 bit mode, it only has access to the 32 bit view of these registry keys. When using the -w switch, the 64 bit view is used and regtool can access the entire registry. This option is simply ignored when running on 32 bit Windows versions. The -W option allows you to access the 32 bit view on the registry. The purpose of this option is mainly for symmetry. It permits creation of OS agnostic scripts which would also work in a hypothetical 64 bit version of Cygwin. You must provide regtool with an action following options (if any). Currently, the action must be add, set, check, get, list, remove, set, or unset. The add action adds a new key. The check action checks to see if a key exists (the exit code of the program is zero if it does, nonzero if it does not). The get action gets the value of a key, and prints it (and nothing else) to stdout. Note: if the value doesn't exist, an error message is printed and the program returns a non-zero exit code. If you give -q, it doesn't print the message but does return the non-zero exit code. The list action lists the subkeys and values belonging to the given key. With list, the -k option instructs regtool to print only KEYs, and the -l option to print only VALUEs. The -p option postfixes a '/' to each KEY, but leave VALUEs with no postfix. The remove action removes a key. Note that you may need to remove everything in the key before you may remove it, but don't rely on this stopping you from accidentally removing too much. The set action sets a value within a key. -b means it's binary data (REG_BINARY). The binary values are specified as hex bytes in the argument list. If the argument is '-', binary data is read from stdin instead. -e means it's an expanding string (REG_EXPAND_SZ) that contains embedded environment variables. -i means the value is an integer (REG_DWORD). -m means it's a multi-string (REG_MULTI_SZ). -s means the value is a string (REG_SZ). If you don't specify one of these, regtool tries to guess the type based on the value you give. If it looks like a number, it's a DWORD. If it starts with a percent, it's an expanding string. If you give multiple values, it's a multi-string. Else, it's a regular string. The unset action removes a value from a key. The load action adds a new subkey and loads the contents of a registry hive into it. The parent key must be HKEY_LOCAL_MACHINE or HKEY_USERS. The unload action unloads the file and removes the subkey. The save action saves a subkey into a registry hive. By default, the last "\" or "/" is assumed to be the separator between the key and the value. You can use the -K option to provide an alternate key/value separator character. Usage: setfacl [-r] (-f ACL_FILE | -s acl_entries) FILE... setfacl [-r] ([-d acl_entries] [-m acl_entries]) FILE... Modify file and directory access control lists (ACLs) -d, --delete delete one or more specified ACL entries -f, --file set ACL entries for FILE to ACL entries read from a ACL_FILE -m, --modify modify one or more specified ACL entries -r, --replace replace mask entry with maximum permissions needed for the file group class -s, --substitute substitute specified ACL entries for the ACL of FILE -h, --help output usage information and exit -v, --version output version information and exit At least one of (-d, -f, -m, -s) must be specified For each file given as parameter, setfacl will either replace its complete ACL (-s, -f), or it will add, modify, or delete ACL entries. For more information on Cygwin and Windows ACLs, see see in the Cygwin User's Guide. Acl_entries are one or more comma-separated ACL entries from the following list: u[ser]::perm u[ser]:uid:perm g[roup]::perm g[roup]:gid:perm m[ask]::perm o[ther]::perm Default entries are like the above with the additional default identifier. For example: d[efault]:u[ser]:uid:perm perm is either a 3-char permissions string in the form "rwx" with the character '-' for no permission or it is the octal representation of the permissions, a value from 0 (equivalent to "---") to 7 ("rwx"). uid is a user name or a numerical uid. gid is a group name or a numerical gid. The following options are supported: -d Delete one or more specified entries from the file's ACL. The owner, group and others entries must not be deleted. Acl_entries to be deleted should be specified without permissions, as in the following list: u[ser]:uid g[roup]:gid d[efault]:u[ser]:uid d[efault]:g[roup]:gid d[efault]:m[ask]: d[efault]:o[ther]: -f Take the Acl_entries from ACL_FILE one per line. Whitespace characters are ignored, and the character "#" may be used to start a comment. The special filename "-" indicates reading from stdin. Note that you can use this with getfacl and setfacl to copy ACLs from one file to another: $ getfacl source_file | setfacl -f - target_file Required entries are: one user entry for the owner of the file, one group entry for the group of the file, and one other entry. If additional user and group entries are given: a mask entry for the file group class of the file, and no duplicate user or group entries with the same uid/gid. If it is a directory: one default user entry for the owner of the file, one default group entry for the group of the file, one default mask entry for the file group class, and one default other entry. -m Add or modify one or more specified ACL entries. Acl_entries is a comma-separated list of entries from the same list as above. -r Causes the permissions specified in the mask entry to be ignored and replaced by the maximum permissions needed for the file group class. -s Like -f, but substitute the file's ACL with Acl_entries specified in a comma-separated list on the command line. While the -d and -m options may be used in the same command, the -f and -s options may be used only exclusively. Directories may contain default ACL entries. Files created in a directory that contains default ACL entries will have permissions according to the combination of the current umask, the explicit permissions requested and the default ACL entries Limitations: Under Cygwin, the default ACL entries are not taken into account currently. Usage: ssp [options] low_pc high_pc command... Single-step profile COMMAND -c, --console-trace trace every EIP value to the console. *Lots* slower. -d, --disable disable single-stepping by default; use OutputDebugString ("ssp on") to enable stepping -e, --enable enable single-stepping by default; use OutputDebugString ("ssp off") to disable stepping -h, --help output usage information and exit -l, --dll enable dll profiling. A chart of relative DLL usage is produced after the run. -s, --sub-threads trace sub-threads too. Dangerous if you have race conditions. -t, --trace-eip trace every EIP value to a file TRACE.SSP. This gets big *fast*. -v, --verbose output verbose messages about debug events. -V, --version output version information and exit Example: ssp 0x401000 0x403000 hello.exe SSP - The Single Step Profiler Original Author: DJ Delorie The SSP is a program that uses the Win32 debug API to run a program one ASM instruction at a time. It records the location of each instruction used, how many times that instruction is used, and all function calls. The results are saved in a format that is usable by the profiling program gprof, although gprof will claim the values are seconds, they really are instruction counts. More on that later. Because the SSP was originally designed to profile the cygwin DLL, it does not automatically select a block of code to report statistics on. You must specify the range of memory addresses to keep track of manually, but it's not hard to figure out what to specify. Use the "objdump" program to determine the bounds of the target's ".text" section. Let's say we're profiling cygwin1.dll. Make sure you've built it with debug symbols (else gprof won't run) and run objdump like this: $ objdump -h cygwin1.dll It will print a report like this: cygwin1.dll: file format pei-i386 Sections: Idx Name Size VMA LMA File off Algn 0 .text 0007ea00 61001000 61001000 00000400 2**2 CONTENTS, ALLOC, LOAD, READONLY, CODE, DATA 1 .data 00008000 61080000 61080000 0007ee00 2**2 CONTENTS, ALLOC, LOAD, DATA . . . The only information we're concerned with are the VMA of the .text section and the VMA of the section after it (sections are usually contiguous; you can also add the Size to the VMA to get the end address). In this case, the VMA is 0x61001000 and the ending address is either 0x61080000 (start of .data method) or 0x0x6107fa00 (VMA+Size method). There are two basic ways to use SSP - either profiling a whole program, or selectively profiling parts of the program. To profile a whole program, just run ssp without options. By default, it will step the whole program. Here's a simple example, using the numbers above: $ ssp 0x61001000 0x61080000 hello.exe This will step the whole program. It will take at least 8 minutes on a PII/300 (yes, really). When it's done, it will create a file called "gmon.out". You can turn this data file into a readable report with gprof: $ gprof -b cygwin1.dll The "-b" means 'skip the help pages'. You can omit this until you're familiar with the report layout. The gprof documentation explains a lot about this report, but ssp changes a few things. For example, the first part of the report reports the amount of time spent in each function, like this: Each sample counts as 0.01 seconds. % cumulative self self total time seconds seconds calls ms/call ms/call name 10.02 231.22 72.43 46 1574.57 1574.57 strcspn 7.95 288.70 57.48 130 442.15 442.15 strncasematch The "seconds" columns are really CPU opcodes, 1/100 second per opcode. So, "231.22" above means 23,122 opcodes. The ms/call values are 10x too big; 1574.57 means 157.457 opcodes per call. Similar adjustments need to be made for the "self" and "children" columns in the second part of the report. OK, so now we've got a huge report that took a long time to generate, and we've identified a spot we want to work on optimizing. Let's say it's the time() function. We can use SSP to selectively profile this function by using OutputDebugString() to control SSP from within the program. Here's a sample program: #include <windows.h> main() { time_t t; OutputDebugString("ssp on"); time(&t); OutputDebugString("ssp off"); } Then, add the -d option to ssp to default to *disabling* profiling. The program will run at full speed until the first OutputDebugString, then step until the second. You can then use gprof (as usual) to see the performance profile for just that portion of the program's execution. There are many options to ssp. Since step-profiling makes your program run about 1,000 times slower than normal, it's best to understand all the options so that you can narrow down the parts of your program you need to single-step. -v - verbose. This prints messages about threads starting and stopping, OutputDebugString calls, DLLs loading, etc. -t and -c - tracing. With -t, *every* step's address is written to the file "trace.ssp". This can be used to help debug functions, since it can trace multiple threads. Clever use of scripts can match addresses with disassembled opcodes if needed. Warning: creates *huge* files, very quickly. -c prints each address to the console, useful for debugging key chunks of assembler. Use addr2line -C -f -s -e foo.exe < trace.ssp > lines.ssp and then perl cvttrace to convert to symbolic traces. -s - subthreads. Usually, you only need to trace the main thread, but sometimes you need to trace all threads, so this enables that. It's also needed when you want to profile a function that only a subthread calls. However, using OutputDebugString automatically enables profiling on the thread that called it, not the main thread. -l - dll profiling. Generates a pretty table of how much time was spent in each dll the program used. No sense optimizing a function in your program if most of the time is spent in the DLL. I usually use the -v, -s, and -l options: $ ssp -v -s -l -d 0x61001000 0x61080000 hello.exe Usage: strace.exe [OPTIONS] <command-line> Usage: strace.exe [OPTIONS] -p <pid> Trace system calls and signals -b, --buffer-size=SIZE set size of output file buffer -d, --no-delta don't display the delta-t microsecond timestamp -f, --trace-children trace child processes (toggle - default true) -h, --help output usage information and exit -m, --mask=MASK set message filter mask -n, --crack-error-numbers output descriptive text instead of error numbers for Windows errors -o, --output=FILENAME set output file to FILENAME -p, --pid=n attach to executing program with cygwin pid n -q, --quiet toggle "quiet" flag. Defaults to on if "-p", off otherwise. -S, --flush-period=PERIOD flush buffered strace output every PERIOD secs -t, --timestamp use an absolute hh:mm:ss timestamp insted of the default microsecond timestamp. Implies -d -T, --toggle toggle tracing in a process already being -u, --usecs toggle printing of microseconds timestamp traced. Requires -p <pid> -v, --version output version information and exit -w, --new-window spawn program under test in a new window MASK can be any combination of the following mnemonics and/or hex values (0x is optional). Combine masks with '+' or ',' like so: --mask=wm+system,malloc+0x00800 Mnemonic Hex Corresponding Def Description ========================================================================= all 0x00001 (_STRACE_ALL) All strace messages. flush 0x00002 (_STRACE_FLUSH) Flush output buffer after each message. inherit 0x00004 (_STRACE_INHERIT) Children inherit mask from parent. uhoh 0x00008 (_STRACE_UHOH) Unusual or weird phenomenon. syscall 0x00010 (_STRACE_SYSCALL) System calls. startup 0x00020 (_STRACE_STARTUP) argc/envp printout at startup. debug 0x00040 (_STRACE_DEBUG) Info to help debugging. paranoid 0x00080 (_STRACE_PARANOID) Paranoid info. termios 0x00100 (_STRACE_TERMIOS) Info for debugging termios stuff. select 0x00200 (_STRACE_SELECT) Info on ugly select internals. wm 0x00400 (_STRACE_WM) Trace Windows msgs (enable _strace_wm). sigp 0x00800 (_STRACE_SIGP) Trace signal and process handling. minimal 0x01000 (_STRACE_MINIMAL) Very minimal strace output. exitdump 0x04000 (_STRACE_EXITDUMP) Dump strace cache on exit. system 0x08000 (_STRACE_SYSTEM) Serious error; goes to console and log. nomutex 0x10000 (_STRACE_NOMUTEX) Don't use mutex for synchronization. malloc 0x20000 (_STRACE_MALLOC) Trace malloc calls. thread 0x40000 (_STRACE_THREAD) Thread-locking calls. The strace program executes a program, and optionally the children of the program, reporting any Cygwin DLL output from the program(s) to stdout, or to a file with the -o option. With the -w option, you can start an strace session in a new window, for example: $ strace -o tracing_output -w sh -c 'while true; do echo "tracing..."; done' & This is particularly useful for strace sessions that take a long time to complete. Note that strace is a standalone Windows program and so does not rely on the Cygwin DLL itself (you can verify this with cygcheck). As a result it does not understand symlinks. This program is mainly useful for debugging the Cygwin DLL itself. Usage: umount.exe [OPTION] [<posixpath>] Unmount filesystems -h, --help output usage information and exit -U, --remove-user-mounts remove all user mounts -v, --version output version information and exit The umount program removes mounts from the mount table in the current session. If you specify a POSIX path that corresponds to a current mount point, umount will remove it from the current mount table. Note that you can only remove user mount points. The -U flag may be used to specify removing all user mount points from the current user session. See for more information on the mount table.