test - check file types and compare values

SYNOPSIS

       test [expr]
       test {--help,--version}

DESCRIPTION

       This  manual page documents the GNU version of test.  Note
       that most shells have a built-in command by the same  name
       and with similar functionality.

       test  returns  a status of 0 (true) or 1 (false) depending
       on the evaluation  of  the  conditional  expression  expr.
       Expressions may be unary or binary.  Unary expressions are
       often used to examine the status of  a  file.   There  are
       string operators and numeric comparison operators as well.

       -b file
              True if file exists and is block special.
       -c file
              True if file exists and is character special.
       -d file
              True if file exists and is a directory.
       -e file
              True if file exists
       -f file
              True if file exists and is a regular file.
       -g file
              True if file exists and is set-group-id.
       -k file
              True if file has its ``sticky'' bit set.
       -L file
              True if file exists and is a symbolic link.
       -p file
              True if file exists and is a named pipe.
       -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.
       -t [fd]
              True if fd is opened on a terminal.  If fd is omit-
              ted, it defaults to 1 (standard output).
       -u file
              True if file exists and its set-user-id bit is set.
       -w file
              True if file exists and is writable.
       -x file
              True if file exists and is executable.
       -O file
       -G file
              True if file exists and is owned by  the  effective
              group id.
       file1 -nt file2
              True  if  file1 is newer (according to modification
              date) than file2.
       file1 -ot file2
              True if file1 is older than file2.
       file1 -ef file2
              True if file1 and file2 have the  same  device  and
              inode numbers.
       -z string
              True if the length of string is zero.
       -n string
       string True if the length of string is non-zero.
       string1 = string2
              True if the strings are equal.
       string1 != string2
              True if the strings are not equal.
       ! expr True if expr is false.
       expr1 -a expr2
              True if both expr1 and expr2 are true.
       expr1 -o expr2
              True if either expr1 or expr2 is true.
       arg1 OP arg2
              OP  is  one  of  -eq,  -ne,  -lt, -le, -gt, or -ge.
              These arithmetic binary operators  return  true  if
              arg1  is equal, not-equal, less-than, less-than-or-
              equal, greater-than, or greater-than-or-equal  than
              arg2,  respectively.  arg1 and arg2 may be positive
              integers, negative integers, or the special expres-
              sion  -l  string,  which evaluates to the length of
              string.
   OPTIONS
       When GNU test is invoked with exactly  one  argument,  the
       following options are recognized:
       --help Print  a  usage message on standard output and exit
              successfully.
       --version
              Print version information on standard  output  then
              exit successfully.