programming:bash:conditionals
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Table of Contents
Conditionals are the primary means of making decisions in programming, especially Bash scripting. Conditionals in Bash are with the [ and [[ built-ins, which are also commands! It makes reasoning about conditionals challenging at first, but there are some useful flags for use with file paths.
Files
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-a file - True if file exists.
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-b file - True if file is an existing block device.
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-c file - True if file is an existing character device
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-d file - True if file is an existing directory.
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-e - See
-a. -
-f file - True if file is an existing normal file.
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-h file - True if file is a symbolic link (symlink).
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-r file - True if file exists and is readable.
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-s file - True if file exists and has a size greater than 0.
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-w file - True if file exists and is writable.
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-x file - True if file exists and is executable.
Variables
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-v arg - True if arg is a set variable.
Bash 4.2+ only.
References
programming/bash/conditionals.1517205444.txt.gz · Last modified: 2018-07-03 01:00 (external edit)