NAME

test − perform tests and return status (sh only)

SYNOPSIS

test expression
[ expression ]

DESCRIPTION

Test evaluates the expression expr, and if its value is true then returns zero exit status; otherwise, a non zero exit status is returned. Test also returns a non zero exit if there are no arguments. 

The following primitives are used to construct expr.

−r file true if the file exists and is readable. 

−w file true if the file exists and is writable. 

−x file true if the file exists and is executable. 

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

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

−c file true if the file exists and is a character device. 

−b file true if the file exists and is a block device. 

−p file true if the file exists and is a named pipe (see mkfifo(1v)).

−u file true if the file exists and the setuid bit is set (bit 04000 in the file mode bits). 

−g file true if the file exists and the setgid bit is set (bit 02000 in the file mode bits). 

−s file true if the 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 nonzero. 

s1 = s2 true if the strings s1 and s2 are equal. 

s1 != s2 true if the strings s1 and s2 are not equal. 

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, or −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. 

( expr ) parentheses for grouping. 

−a has higher precedence than −o.  Notice that all the operators and flags are separate arguments to test. Notice also that parentheses are meaningful to the Shell and must be escaped.

When using the command [ the command must be followed by a space and the final ] must be given and preceded by a space. 

NOTES

The command is a shell built-in.  Programs with identical names exist but have slightly different semantics − see test(1).

SEE ALSO

sh(1), test(1), expr(1).

System V