test(1)test(1)NAMEtest - condition evaluation command
SYNOPSIS
expr
DESCRIPTION
The command evaluates the expression expr and, if its value is True,
returns a zero (true) exit status; otherwise, a nonzero (false) exit
status is returned. also returns a nonzero exit status if there are no
arguments. The following primitives are used to construct expr:
True if file exists and is readable.
True if file exists and is writable.
True if file exists and is executable.
True if file exists and is a regular file.
True if file exists and is a directory.
True if file exists and is a character special file.
True if file exists and is a block special file.
True if file exists and is a named pipe (fifo).
True if file exists and its set-user-ID bit is set.
True if file exists and its set-group-ID bit is set.
True if file exists and its sticky bit is set.
True if file exists and has a size greater than zero.
True if file exists and is a symbolic link.
True if the open file whose file descriptor number is
fildes (1 by default) is associated with a termi‐
nal device.
True if the length of string
s1 is zero.
True if the length of the string
s1 is non-zero.
True if strings
s1 and s2 are identical.
True if strings
s1 and s2 are not identical.
s1 True if s1 is not the null string.
True if the integers
n1 and n2 are algebraically equal. Any of the
comparisons and can be used in place of
These primaries can be combined with the following operators:
Unary negation operator.
Binary AND operator.
Binary OR operator
has higher precedence than
Parentheses for grouping.
Note that all the operators and flags are separate arguments to Note
also that parentheses are significant to the shell and therefore must
be escaped. All file test operators return success if the argument is
a symbolic link that points to a file of the file type being tested.
is interpreted directly by the shell, and therefore does not exist as a
separate executable program.
EXTERNAL INFLUENCES
International Code Set Support
Single byte and multibyte character code sets are supported.
EXAMPLES
Exit if there are not two or three arguments:
Create a new file containing the text string if the file does not
already exist:
Wait for myfile to become non-readable:
WARNINGS
When the form of this command is used, the matching must be the final
argument, and both must be separate arguments from the arguments they
enclose (white space delimiters required.
Parentheses and other special shell metacharacters intended to be han‐
dled by test must be escaped or quoted when invoking from a shell.
Avoid such problems when comparing strings by inserting a non-operator
character at the beginning of both operands:
This approach does not work with numeric comparisons or the unary oper‐
ators because it would affect the operand being checked.
AUTHOR
was developed by the University of California, Berkeley and HP.
SEE ALSOfind(1), sh-posix(1), sh(1).
STANDARDS CONFORMANCEtest(1)
