test - condition evaluation utility

NAME SYNOPSIS DESCRIPTION RETURN VALUES CAVEATS SEE ALSO

The test utility evaluates the expression and, if it evaluates to true, returns a zero (true) exit status; otherwise it returns 1 (false). If no expression is given, 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 for COMPATABILITY purposes, 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 by the effective user/group.
	−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.

	−t		Same as above with an implicit file descriptor number of "1" (e.g.: −t 1).
	−u file		True if file exists and its set−user−ID flag is set.
	−w file		True if file exists and is writable by the effective user/group. 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 by the effective user/group. 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.
	−B file		True if file exists and is a binary file.
	−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.
	−R file		True if file exists and is readable by the real user/group.
	−S file		True if file exists and is a socket.
	−T file		True if file exists and is a text file.
	−W file		True if file exists and is writable by the real user/group. 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 by the real user/group. True indicates only that the execute flag is on. If file is a directory, true indicates that file can be searched.

file1 −nt file2

True if file1 exists and is newer than file2.

file1 −ot file2

True if file1 exists and is older than file2.

	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 integer 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 (uses parentheses for grouping).

Note that the −a operator has higher precedence than the −o operator. Notice also that all the operators and flags are separate arguments to test.

RETURN VALUES

The test utility exits with one of the following values:
$return_val == 0

Expression evaluated to true.

$return_val == 1

Expression evaluated to false or expression was missing.

$return_val > 1

An error occurred.

CAVEATS

Command line arguments like parentheses and arithmetic operators (e.g.: '(', ')', '!', '>', '<', etc.) may be meaningful to the command−line interpreter (shell) and therefore may need to be escaped from any special shell interpretation.