66 lines
1.5 KiB
Plaintext
66 lines
1.5 KiB
Plaintext
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Command: test, [ - test for a condition
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Syntax: test expr
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[ expr ]
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Flags: (none)
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Example: test -r file # See if file is readable
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Test checks to see if files exist, are readable, etc. and returns
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an exit status of zero if true and nonzero if false. The legal
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operators are
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-r file true if the file is readable
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-w file true if the file is writable
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-x file true if the file is executable
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-f file true if the file is not a directory
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-d file true if the file is a directory
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-s file true if the file exists and has a size > 0
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-t fd true if file descriptor fd (default 1) is a terminal
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-z s true if the string s has zero length
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-n s true if the string s has nonzero length
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s1 = s2 true if the strings s1 and s2 are identical
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s1 != s2 true if the strings s1 and s2 are different
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m -eq m true if the integers m and n are numerically equal
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The operators -gt, -ge, -ne, -le, and -lt may be used as well. These
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operands may be combined with -a (Boolean and), -o (Boolean or), !
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(negation). The priority of -a is higher than that of -o. Parentheses
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are permitted, but must be escaped to keep the shell from trying to
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interpret them.
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