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test (1)
  • >> test (1) ( Solaris man: Команды и прикладные программы пользовательского уровня )
  • test (1) ( FreeBSD man: Команды и прикладные программы пользовательского уровня )
  • test (1) ( Русские man: Команды и прикладные программы пользовательского уровня )
  • test (1) ( Linux man: Команды и прикладные программы пользовательского уровня )
  • test (1) ( POSIX man: Команды и прикладные программы пользовательского уровня )
  • Ключ test обнаружен в базе ключевых слов.
  •  

    NAME

    test - evaluate condition(s)
     
    

    SYNOPSIS

    /usr/bin/test [condition]
    

    [ [condition] ]
    

     

    sh

    test [condition]
    

    [ [condition] ]
    

     

    csh

    test [condition]
    

    [ [condition] ]
    

     

    ksh

    test [condition]
    

    [ [condition] ]
    

     

    ksh93

    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. condition 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 is returned even though the file can have the group or other bit set for that permission.

    The = and != primaries have a higher precedence than the unary primaries. 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 special 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 returns true if file exists and is (not-a-directory). 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. This option is not available in csh or sh.

    -O file

    True if file exists and is owned by the effective user ID of this process. This option is 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. This option is not available in sh.

    -t [file_descriptor]

    True if the file whose file descriptor number is file_descriptor is open and is associated 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 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. 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 string is zero.

    file1 -nt file2

    True if file1 exists and is newer than file2. This option is not available in sh.

    file1 -ot file2

    True if file1 exists and is older than file2. This option is not available in sh.

    file1 -ef file2

    True if file1 and file2 exist and refer to the same file. This option is 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 algebraically equal. ksh93 also supports floating point numbers.

    n1 -ne n2

    True if the integers n1 and n2 are not algebraically equal. ksh93 also supports floating point numbers

    n1 -gt n2

    True if the integer n1 is algebraically greater than the integer n2. ksh93 also supports floating point numbers

    n1 -ge n2

    True if the integer n1 is algebraically greater than or equal to the integer n2. ksh93 also supports floating point numbers

    n1 -lt n2

    True if the integer n1 is algebraically less than the integer n2. ksh93 also supports floating point numbers

    n1 -le n2

    True if the integer n1 is algebraically less than or equal to the integer n2. ksh93 also supports floating point numbers

    condition1 -a condition2

    True if both condition1 and condition2 are true. The -a binary primary is left associative 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 associative.

    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. The 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 is generated is based on the number of arguments presented to test. (However, when using the [...] form, the right-bracket final argument is not counted in this algorithm.)

    In the following list, $1, $2, $3 and $4 represent the arguments presented 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, invocations 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 portability 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 construct:

    test "$response" = "expected string"
    

    One of the following is a more reliable form:

    test "X$response" = "Xexpected string"
    test "expected string" = "$response"
    

    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 occur if $1 evaluates to ( or !. One of the following 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 variations), 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
    

    Example 2 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
    

     

    The test built-in

    The two forms of the test built-in follow the Bourne shell's if example.

    Example 3 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 4 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 5 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 6 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
    

     

    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:  

    /usr/bin/test, csh, ksh, sh

    ATTRIBUTE TYPEATTRIBUTE VALUE

    AvailabilitySUNWcsu

    Interface Stability

    Standard

     

    ksh93

    ATTRIBUTE TYPEATTRIBUTE VALUE

    AvailabilitySUNWcsu

    Interface Stability

     

    SEE ALSO

    csh(1), ksh(1), ksh93(1), sh(1), test(1B), attributes(5), environ(5), largefile(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.

    When comparing file timestamps, the ksh93 test built-in handles high-resolution timestamps of up to nanosecond granularity, for file systems which support them.


     

    Index

    NAME
    SYNOPSIS
    sh
    csh
    ksh
    ksh93
    DESCRIPTION
    OPERANDS
    USAGE
    EXAMPLES
    /usr/bin/test
    The test built-in
    csh
    ksh
    ENVIRONMENT VARIABLES
    EXIT STATUS
    ATTRIBUTES
    /usr/bin/test, csh, ksh, sh
    ksh93
    SEE ALSO
    NOTES


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