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(gawk.info)Special Process

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Special Files for Process-Related Information
---------------------------------------------

   `gawk' also provides special file names that give access to
information about the running `gawk' process.  Each of these "files"
provides a single record of information.  To read them more than once,
they must first be closed with the `close' function (Note: Closing
Input and Output Redirections.).  The file names
are:

`/dev/pid'
     Reading this file returns the process ID of the current process,
     in decimal form, terminated with a newline.

`/dev/ppid'
     Reading this file returns the parent process ID of the current
     process, in decimal form, terminated with a newline.

`/dev/pgrpid'
     Reading this file returns the process group ID of the current
     process, in decimal form, terminated with a newline.

`/dev/user'
     Reading this file returns a single record terminated with a
     newline.  The fields are separated with spaces.  The fields
     represent the following information:

    `$1'
          The return value of the `getuid' system call (the real user
          ID number).

    `$2'
          The return value of the `geteuid' system call (the effective
          user ID number).

    `$3'
          The return value of the `getgid' system call (the real group
          ID number).

    `$4'
          The return value of the `getegid' system call (the effective
          group ID number).

     If there are any additional fields, they are the group IDs
     returned by the `getgroups' system call.  (Multiple groups may not
     be supported on all systems.)

   These special file names may be used on the command line as data
files, as well as for I/O redirections within an `awk' program.  They
may not be used as source files with the `-f' option.

   *Note:* The special files that provide process-related information
are now considered obsolete and will disappear entirely in the next
release of `gawk'.  `gawk' prints a warning message every time you use
one of these files.  To obtain process-related information, use the
`PROCINFO' array.  *Note Built-in Variables That Convey Information:
Auto-set.