lua-osx/examples/cat.lua

82 lines
1.6 KiB
Lua

#!/bin/env lua
-- Trimmed down cat(1) utility.
--
-- Concatenate files to stdout, making sure bytes are actually written
-- out successfully.
--
-- SYNOPSIS:
-- cat.lua [-u] <FILES...>
--
-- NOTE: utility doesn't explicitly allow to concatenate stdin.
--
-- Author: Lorenzo Cogotti, The DoubleFourteen Code Forge
local osx = require 'osx'
local io = require 'io'
local uflag = false
local function cat(path)
local ferr = io.stderr
local f, err = io.open(path, 'r')
if err then
ferr:write(err, "\n")
return false
end
local success = true -- unless it happens to be a failure
local fout = io.stdout
while true do
local buf, err = f:read(4096)
if err then
ferr:write(err, "\n")
success = false
end
if not buf then
break -- done with file
end
assert(fout:write(buf))
end
f:close()
assert(fout:flush())
if not osx.isatty(fout) then
assert(osx.commit(fout))
end
return success
end
local function parseargs(...)
local files = {}
for i = 1, select('#', ...) do
local arg = select(i, ...)
if arg == '-u' then
uflag = true
else
files[#files+1] = arg
end
end
if #files == 0 then
error("Missing file arguments")
end
return files
end
local files = parseargs(...)
io.stdout:setvbuf(uflag and 'no' or 'full')
local success = true
for _, path in ipairs(files) do
if not cat(path) then
success = false
end
end
if not success then
os.exit(1)
end