NAME

test − condition evaluation command

SYNOPSIS

test expr
[ expr ]

DESCRIPTION

Test evaluates the expression expr and, if its value is true, returns a zero (true) exit status; otherwise, a non-zero (false) exit status is returned; test also returns a non-zero exit status if there are no arguments.  The following primitives are used to construct expr:

−r file true if file exists and is readable.

−w file true if file exists and is writable.

−x file true if file exists and is executable. 

−f file true if file exists and is a regular file.

−d file true if file exists and is a directory.

−c file true if file exists and is a character special file. 

−b file true if file exists and is a block special file. 

−p file true if file exists and is a named pipe (fifo). 

−u file true if file exists and its set-user- ID bit is set. 

−g file true if file exists and its set-group- ID bit is set. 

−k file true if file exists and its sticky bit is set. 

−s file true if file exists and has a size greater than zero.

−t [fildes] true if the open file whose file descriptor number is fildes (1 by default) is associated with a terminal device. 

−z s1 true if the length of string s1 is zero. 

−n s1 true if the length of the string s1 is non-zero. 

s1 = s2 true if strings s1 and s2 are identical. 

s1 != s2 true if strings s1 and s2 are not identical. 

s1 true if s1 is not the null string. 

n1−eq n2 true if the integers n1 and n2 are algebraically equal.  Any of the comparisons −ne, −gt, −ge, −lt, and −le may be used in place of −eq. 

These primaries may be combined with the following operators:

!  unary negation operator. 

−a binary and operator. 

−o binary or operator (−a has higher precedence than −o). 

(expr) parentheses for grouping. 

Notice that all the operators and flags are separate arguments to test. Notice also that parentheses are meaningful to the shell and, therefore, must be escaped. Also realize that test is both a builtin of the Bourne shell and an executable program in /bin that may be used by either shell. 

EXAMPLE

Test is typically used in shell scripts (sh(1)), as in the following example which prints the message "foo is a dir" if foo is a directory. 

if test -d foo
then
echo "foo is a dir"
fi

SEE ALSO

find(1), sh(1). 

WARNING

In the second form of the command (i.e., the one that uses [], rather than the word test), the square brackets must be delimited by blanks.

Version 2.5r1  —  October 29, 1986