test

Condition evaluation.
Evaluate an expression and, if it evaluates to true, return a zero (true) exit status; otherwise return 1 (false). If there is no expression, test also returns 1 (false).

SYNTAX
      test expression

OPTIONS
The following primaries are used to construct expression:

     -b file       True if file exists and is a block special file.

     -c file       True if file exists and is a character special file.

     -d file       True if file exists and is a directory.

     -e file       True if file exists (regardless of type).

     -f file       True if file exists and is a regular file.

     -g file       True if file exists and its set group ID flag is set.

     -h file       True if file exists and is a symbolic link.  This operator
                   is retained for compatibility with previous versions of
                   this program. Do not rely on its existence; use -L instead.

     -k file       True if file exists and its sticky bit is set.

     -n string     True if the length of string is nonzero.

     -p file       True if file is a named pipe (FIFO).

     -r file       True if file exists and is readable.

     -s file       True if file exists and has a size greater than zero.

     -t file_descriptor

                   True if the file whose file descriptor number is
                   file_descriptor is open and is associated with a terminal.

     -u file       True if file exists and its set user ID flag is set.

     -w file       True if file exists and is writable.  True indicates only
                   that the write flag is on.  The file is not writable on a
                   read-only file system even if this test indicates true.

     -x file       True if file exists and is executable.  True indicates only
                   that the execute flag is on.  If file is a directory, true
                   indicates that file can be searched.

     -z string     True if the length of string is zero.

     -L file       True if file exists and is a symbolic link.

     -O file       True if file exists and its owner matches the effective us-
                   er id of this process.

     -G file       True if file exists and its group matches the effective
                   group id of this process.

     -S file       True if file exists and is a socket.

     file1 -nt file2

                   True if file1 exists and is newer than file2.

     file1 -ot file2
                   True if file1 exists and is older than file2.

     file1 -ef file2

                   True if file1 and file2 exist and refer to the same file.

     string        True if string is not the null string.

     s1 = s2       True if the strings s1 and s2 are identical.

     s1 != s2      True if the strings s1 and s2 are not identical.

     s1 < s2       True if string s1 comes before s2 based on the ASCII value
                   of their characters.

     s1 > s2       True if string s1 comes after s2 based on the ASCII value
                   of their characters.

     s1            True if s1 is not the null string.

     n1 -eq n2     True if the integers n1 and n2 are algebraically equal.

     n1 -ne n2     True if the integers n1 and n2 are not algebraically equal.

     n1 -gt n2     True if the integer n1 is algebraically greater than the
                   integer n2.

     n1 -ge n2     True if the integer n1 is algebraically greater than or
                   equal to the integer n2.

     n1 -lt n2     True if the integer n1 is algebraically less than the inte-
                   ger n2.

     n1 -le n2     True if the integer n1 is algebraically less than or equal
                   to the integer n2.

     These primaries can be combined with the following operators:

     ! expression  True if expression is false.

     expression1 -a expression2

                   True if both expression1 and expression2 are true.

     expression1 -o expression2
                   True if either expression1 or expression2 are true.

     (expression)  True if expression is true.

     The -a operator has higher precedence than the -o operator.

The test utility exits with one of the following values:

     0       expression evaluated to true.
     1       expression evaluated to false or expression was missing.
     >1      An error occurred.

"The test of a vocation is the love of the drudgery it involves" - Logan Pearsall

Related commands:

eval - Evaluate several commands/arguments
expr - Evaluate expressions

Equivalent BASH command:

test