43 lines
957 B
Lua
43 lines
957 B
Lua
#!/bin/env lua
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-- Stripped down version of coreutils truncate(1).
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--
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-- SYNOPSIS:
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-- truncate.lua <size> <file>
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--
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-- Size may have a suffix: K (kilobytes), M (megabytes), G (gigabytes) with K = 1024
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--
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-- Example use:
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-- lua truncate.lua 10K myfile
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--
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-- Author: Lorenzo Cogotti, The DoubleFourteen Code Forge
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local osx = require 'osx'
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local size = assert(select(1, ...), "Missing size argument")
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local path = assert(select(2, ...), "Missing file path")
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local function parsesize(s)
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local u = s:sub(-1)
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local scale = 1
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if u == 'K' then
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scale = 1024
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s = s:sub(1, -2)
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elseif u == 'M' then
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scale = 1024*1024
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s = s:sub(1, -2)
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elseif u == 'G' then
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scale = 1024*1024*1024
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s = s:sub(1, -2)
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end
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local v = tonumber(s)
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if not v or v < 0 then
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error("'"..s.."' is not a valid file size")
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end
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return v * scale
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end
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size = parsesize(size)
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assert(osx.chsize(path, size))
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