test(1) User Commands test(1)NAMEtest - evaluate condition(s)SYNOPSIS
/usr/bin/test [condition]
[ [condition] ]
sh
test [condition]
[ [condition] ]
csh
test [condition]
[ [condition] ]
ksh
test [condition]
[ [condition] ]
DESCRIPTION
The test utility evaluates the condition and indicates the result of
the evaluation by its exit status. An exit status of zero indicates
that the condition evaluated as true and an exit status of 1 indicates
that the condition evaluated as false.
In the first form of the utility shown using the SYNOPSIS:
test [ condition ]
the square brackets denote that condition is an optional operand and
are not to be entered on the command line.
In the second form of the utility shown using the SYNOPSIS:
[ [ condition ] ]
the first open square bracket, [, is the required utility name. condi‐
tion is optional, as denoted by the inner pair of square brackets. The
final close square bracket, ], is a required operand.
See largefile(5) for the description of the behavior of test when
encountering files greater than or equal to 2 Gbyte (2^31 bytes).
The test and [ utilities evaluate the condition condition and, if its
value is true, set exit status to 0. Otherwise, a non-zero (false) exit
status is set. test and [ also set a non-zero exit status if there are
no arguments. When permissions are tested, the effective user ID of the
process is used.
All operators, flags, and brackets (brackets used as shown in the last
SYNOPSIS line) must be separate arguments to these commands. Normally
these arguments are separated by spaces.
OPERANDS
The primaries listed below with two elements of the form:
-primary_operator primary_operand
are known as unary primaries. The primaries with three elements in
either of the two forms:
primary_operand -primary_operator primary_operand
primary_operand primary_operator primary_operand
are known as binary primaries.
If any file operands except for -h and -L primaries refer to symbolic
links, the symbolic link is expanded and the test is performed on the
resulting file.
If you test a file you own (the -r -w or -x tests), but the permission
tested does not have the owner bit set, a non-zero (false) exit status
will be returned even though the file may have the group or other bit
set for that permission.
The = and != primaries have a higher precedence than the unary pri‐
maries. The = and != primaries always expect arguments; therefore, =
and != cannot be used as an argument to the unary primaries.
The following primaries can be used to construct condition:
-a file True if file exists. (Not available in sh.)
-b file True if file exists and is a block special
file.
-c file True if file exists and is a character spe‐
cial file.
-d file True if file exists and is a directory.
-e file True if file exists. (Not available in sh.)
-f file True if file exists and is a regular file.
Alternatively, if /usr/bin/sh users specify
/usr/ucb before /usr/bin in their PATH
environment variable, then test will return
true if file exists and is (not−a−direc‐
tory). The csh test and [ built-ins always
use this alternative behavior.
-g file True if file exists and its set group ID
flag is set.
-G file True if file exists and its group matches
the effective group ID of this process.
(Not available in sh.)
-h file True if file exists and is a symbolic link.
-k file True if file exists and has its sticky bit
set.
-L file True if file exists and is a symbolic link.
-n string True if the length of string is non-zero.
-o option True if option named option is on. (Not
available in csh or sh.)
-O file True if file exists and is owned by the
effective user ID of this process. (Not
available in sh.)
-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.
-S file True if file exists and is a socket. (Not
available in sh.)
-t [file_descriptor] True if the file whose file descriptor num‐
ber is file_descriptor is open and is asso‐
ciated with a terminal. If file_descriptor
is not specified, 1 is used as a default
value.
-u file True if file exists and its set-user-ID
flag is set.
-w file True if file exists and is writable. True
will indicate only that the write flag is
on. The file will not be writable on a
read-only file system even if this test
indicates true.
-x file True if file exists and is executable. True
will indicate 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 string is
zero.
file1 -nt file2 True if file1 exists and is newer than
file2. (Not available in sh.)
file1 -ot file2 True if file1 exists and is older than
file2. (Not available in sh.)
file1 -ef file2 True if file1 and file2 exist and refer to
the same file. (Not available in sh.)
string True if the string string is not the null
string.
string1 = string2 True if the strings string1 and string2 are
identical.
string1 != string2 True if the strings string1 and string2 are
not identical.
n1 -eq n2 True if the integers n1 and n2 are algebra‐
ically equal.
n1 -ne n2 True if the integers n1 and n2 are not al‐
gebraically 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.
condition1 -a condition2 True if both condition1 and condition2 are
true. The -a binary primary is left asso‐
ciative and has higher precedence than the
-o binary primary.
condition1 -o condition2 True if either condition1 or condition2 is
true. The -o binary primary is left asso‐
ciative.
These primaries can be combined with the following operators:
! condition True if condition is false.
( condition ) True if condition is true. The parentheses ( ) can be
used to alter the normal precedence and associativity.
Notice also that parentheses are meaningful to the
shell and, therefore, must be quoted.
The algorithm for determining the precedence of the operators and the
return value that will be generated is based on the number of arguments
presented to test. (However, when using the [...] form, the right-
bracket final argument will not be counted in this algorithm.)
In the following list, $1, $2, $3 and $4 represent the arguments pre‐
sented to test as a condition, condition1, or condition2.
0 arguments: Exit false (1).
1 argument: Exit true (0) if $1 is not null. Otherwise, exit false.
2 arguments:
o If $1 is !, exit true if $2 is null, false
if $2 is not null.
o If $1 is a unary primary, exit true if the
unary test is true, false if the unary test
is false.
o Otherwise, produce unspecified results.
3 arguments:
o If $2 is a binary primary, perform the
binary test of $1 and $3.
o If $1 is !, negate the two-argument test of
$2 and $3.
o Otherwise, produce unspecified results.
4 arguments:
o If $1 is !, negate the three-argument test
of $2, $3, and $4.
o Otherwise, the results are unspecified.
USAGE
Scripts should be careful when dealing with user-supplied input that
could be confused with primaries and operators. Unless the application
writer knows all the cases that produce input to the script, invoca‐
tions like test "$1" -a "$2" should be written as test "$1" && test
"$2" to avoid problems if a user supplied values such as $1 set to !
and $2 set to the null string. That is, in cases where maximal porta‐
bility is of concern, replace test expr1 -a expr2 with test expr1 &&
test expr2, and replace test expr1 -o expr2 with test expr1 || test
expr2. But notice that, in test, -a has higher precedence than -o,
while && and || have equal precedence in the shell.
Parentheses or braces can be used in the shell command language to
effect grouping.
Parentheses must be escaped when using sh. For example:
test \( expr1 -a expr2 \) -o expr3
This command is not always portable outside XSI-conformant systems. The
following form can be used instead:
( test expr1 && test expr2 ) || test expr3
The two commands:
test "$1"
test ! "$1"
could not be used reliably on some historical systems. Unexpected
results would occur if such a string condition were used and $1
expanded to !, (, or a known unary primary. Better constructs are,
respectively,
test-n "$1"
test-z "$1"
Historical systems have also been unreliable given the common con‐
struct:
test "$response" = "expected string"
One of the following is a more reliable form:
test "X$response" = "Xexpected string"
test "expected string" = "$response"
Notice that the second form assumes that expected string could not be
confused with any unary primary. If expected string starts with −, (, !
or even =, the first form should be used instead. Using the preceding
rules without the marked extensions, any of the three comparison forms
is reliable, given any input. (However, observe that the strings are
quoted in all cases.)
Because the string comparison binary primaries, = and !=, have a higher
precedence than any unary primary in the >4 argument case, unexpected
results can occur if arguments are not properly prepared. For example,
in
test-d $1 -o -d $2
If $1 evaluates to a possible directory name of =, the first three
arguments are considered a string comparison, which causes a syntax
error when the second -d is encountered. is encountered. One of the
following forms prevents this; the second is preferred:
test \( -d "$1" \) -o \( -d "$2" \)
test-d "$1" || test-d "$2"
Also in the >4 argument case:
test "$1" = "bat" -a "$2" = "ball"
Syntax errors will occur if $1 evaluates to ( or !. One of the follow‐
ing forms prevents this; the third is preferred:
test "X$1" = "Xbat" -a "X$2" = "Xball"
test "$1" = "bat" && test "$2" = "ball"
test "X$1" = "Xbat" && test "X$2" = "Xball"
EXAMPLES
In the if command examples, three conditions are tested, and if all
three evaluate as true or successful, then their validities are written
to the screen. The three tests are:
o if a variable set to 1 is greater than 0,
o if a variable set to 2 is equal to 2, and
o if the word root is included in the text file /etc/passwd.
/usr/bin/test
Example 1 Using /usr/bin/test
Perform a mkdir if a directory does not exist:
test ! -d tempdir && mkdir tempdir
Wait for a file to become non-readable:
while test-r thefile
do
sleep 30
done
echo'"thefile" is no longer readable'
Perform a command if the argument is one of three strings (two varia‐
tions), using the open bracket version [ of the test command:
if [ "$1" = "pear" ] || [ "$1" = "grape" ] || [ "$1" = "apple" ]
then
command
fi
case "$1" in
pear|grape|apple) command;;
esac
The test built-in
The two forms of the test built-in follow the Bourne shell's if exam‐
ple.
Example 2 Using the sh built-in
ZERO=0 ONE=1 TWO=2 ROOT=root
if [ $ONE -gt $ZERO ]
[ $TWO -eq 2 ]
grep $ROOT /etc/passwd >&1 > /dev/null # discard output
then
echo "$ONE is greater than 0, $TWO equals 2, and $ROOT is" \
"a user-name in the password file"
else
echo "At least one of the three test conditions is false"
fi
Example 3 Using the test built-in
Examples of the test built-in:
test `grep $ROOT /etc/passwd >&1 /dev/null` # discard output
echo $? # test for success
[ `grep nosuchname /etc/passwd >&1 /dev/null` ]
echo $? # test for failure
csh
Example 4 Using the csh built-in
@ ZERO = 0; @ ONE = 1; @ TWO = 2; set ROOT = root
grep $ROOT /etc/passwd >&1 /dev/null # discard output
# $status must be tested for immediately following grep
if ( "$status" == "0" && $ONE > $ZERO && $TWO == 2 ) then
echo "$ONE is greater than 0, $TWO equals 2, and $ROOT is" \
"a user-name in the password file"
endif
ksh
Example 5 Using the ksh built-in
ZERO=0 ONE=1 TWO=$((ONE+ONE)) ROOT=root
if ((ONE > ZERO)) # arithmetical comparison
[[ $TWO = 2 ]] # string comparison
[ `grep $ROOT /etc/passwd >&1 /dev/null` ] # discard output
then
echo "$ONE is greater than 0, $TWO equals 2, and $ROOT is" \
"a user-name in the password file"
else
echo "At least one of the three test conditions is false"
fi
Using -e option in sh
Example 6 Using /usr/bin/test for the -e option
If one really wants to use the -e option in sh, use /usr/bin/test, as
in the following:
if [ ! -h $PKG_INSTALL_ROOT$rLink ] && /usr/bin/test -e
$PKG_INSTALL_ROOT/usr/bin/$rFile ; then
ln -s $rFile $PKG_INSTALL_ROOT$rLink
fi
ENVIRONMENT VARIABLES
See environ(5) for descriptions of the following environment variables
that affect the execution of test: LANG, LC_ALL, LC_CTYPE, LC_MESSAGES,
and NLSPATH.
EXIT STATUS
The following exit values are returned:
0 condition evaluated to true.
1 condition evaluated to false or condition was missing.
>1 An error occurred.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Availability │SUNWcsu │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Standard │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOcsh(1), ksh(1), sh(1), test(1B), attributes(5), environ(5), large‐
file(5), standards(5)NOTES
The not−a−directory alternative to the -f option is a transition aid
for BSD applications and may not be supported in future releases.
SunOS 5.10 23 Aug 2002 test(1)
