Unix in a Nutshell, 4th Edition

Name

test

Synopsis

    test condition
             or
    [ condition ]
             or
    [[ condition ]]

Evaluate a condition and, if its value is true, return a zero exit status; otherwise, return a nonzero exit status. An alternate form of the command uses [ ] rather than the word test. An additional alternate form uses [[ ]], in which case word splitting and pathname expansion are not done. (See the [[ ]] entry.) condition is constructed using the following expressions. Conditions are true if the description holds true. Features that are specific to Bash are marked with a (B). Features that are specific to the Korn shell are marked with a (K). Features that are specific to ksh93 are marked with a (K93).

File Conditions

-a file	file exists.
-b file	file exists and is a block special file.
-c file	file exists and is a character special file.
-C file	(K) file exists and is a contiguous file. This facility is not available on most Unix systems.
-d file	file exists and is a directory.
-f file	file exists and is a regular file.
-g file	file exists, and its set-group-id bit is set.
-G file	file exists, and its group is the effective group ID.
-h file	file exists and is a symbolic link.
-k file	file exists, and its sticky bit is set.
-L file	file exists and is a symbolic link.
-N file	(B) file exists and was modified after it was last read.
-O file	file exists, and its owner is the effective user ID.
-p file	file exists and is a named pipe (FIFO).
-r file	file exists ...