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test

condition evaluation utility

Synopsis

     test expression
     [ expression ]

Description

The test utility evaluates the expression and, if it evaluates to true, returns a zero (true) exit status; otherwise it returns 1 (false). If there is no expression, test also returns 1 (false).

All operators and flags are separate arguments to the test utility.

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 user 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 binary value of their characters.

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

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 integer n2.

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

If file is a symbolic link, test will fully dereference it and then evaluate the expression against the file referenced, except for the -h and -L primaries.

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.

Some shells may provide a builtin test command which is similar or identical to this utility. Consult the builtin(1) manual page.

Grammar Ambiguity

The test grammar is inherently ambiguous. In order to assure a degree of consistency, the cases described in the IEEE Std 1003.2 (“POSIX.2”), section D11.2/4.62.4, standard are evaluated consistently according to the rules specified in the standards document. All other cases are subject to the ambiguity in the command semantics.

In particular, only expressions containing -a, -o, ( or ) can be ambiguous.

Exit Status

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.

Examples

     Implement test FILE1 -nt FILE2 using only POSIX functionality:

	   test -n "$(find -L -- FILE1 -prune -newer FILE2 2>/dev/null)"

     This can be modified using non-standard find(1) primaries like -newerca to compare other
     timestamps.

Compatibility

For compatibility with some other implementations, the = primary can be substituted with == with the same meaning.

See Also

builtin(1), expr(1), find(1), sh(1), stat(1), symlink(7)

Standards

The test utility implements a superset of the IEEE Std 1003.2 (“POSIX.2”) specification. The primaries <, ==, >, -ef, -nt, -ot, -G, and -O are extensions.

History

A test utility appeared in Version 7 AT&T UNIX.

Bugs

Both sides are always evaluated in -a and -o. For instance, the writable status of file will be tested by the following command even though the former expression indicated false, which results in a gratuitous access to the file system: [ -z abc -a -w file ] To avoid this, write [ -z abc ] && [ -w file ]

macOS 26.4 October 5, 2016 macOS 26.4