nohup

PURPOSE

     Runs a command without hangups and quits.

SYNOPSIS
     nohup command [ arguments ]


DESCRIPTION

     The nohup command runs  command, ignoring all hangups and
     quit signals.  You  can use this command  to run programs
     in the  background after you  log off of the  system.  To
     run a nohup command in the  background, add an "&" to the
     end of the command.

     If nohup  output is  redirected to a  terminal or  is not
     redirected at all, the output goes to the file nohup.out.
     If nohup.out  is not  writable in the  current directory,
     the output is redirected to $HOME/nohup.out.

     The syntax of this command  ignores quits and hangups for
     only one command.  If you want  to apply nohup to a pipe-
     line or  list of  commands, you can  put the  pipeline or
     list in a shell script file.   Then you can run sh as the
     command using the format: "nohup  sh" file.  You can also
     assign the  shell file execute  permission and run  it as
     the command in the form:  "nohup" file.

EXAMPLES

     1.  To leave a command running after you log out:

           nohup  find  /  -print  &

         Shortly after  you enter this, the  following is dis-
         played:

           670
           $ Sending output to nohup.out

         The number  will probably  be different when  you use
         this command.  It is the ID of the background process
         started by "&" (ampersand).  (See page about starting
         background  processes  with  "&".)  The  "$"  (dollar
         sign) is your shell prompt.   "Sending output . . . "
         is  a  message from  nohup  telling  you that  it  is
         storing the  output from  the ".find" command  in the
         file  "nohup.out".  You  can  log out  after you  see
         these messages,  even if  the "find" command  has not
         finished yet.
     2.  To do  the same, but redirecting  the standard output
         to a different file:

           nohup  find  /  -print  >filenames  &

         This runs the "find" command and stores its output in
         a file  named "filenames".   Now only the  process ID
         and your prompt are displayed:

           677
           $

         Wait for a second or  two before logging off, because
         the nohup command takes a moment to start the command
         you  specified.  If  you  log off  too quickly,  your
         command may  not run at  all.  Once your  command has
         started, logging off will not affect it.
     3.  To run more than one  command, use a shell procedure.
         For example, if you write the shell procedure:

           neqn math1 ] nroff > fmath1

         and name it "nnfmath1", you  can run nohup for all of
         the commands in "nnfmath1" with the command:

           nohup sh nnmath1

         If you assign "nnfmath1"  execute permission, you can
         obtain the same results by issuing the command:

           nohup nnmath1

         To  run this  command  in the  background, enter  the
         command:

           nohup nnmath1 &

RELATED INFORMATION

     The following commands:  "csh,"  "nice," and "sh."

     Note:   The csh  command contains  a built-in  subcommand
     named nohup.   The command  and subcommand do  not neces-
     sarily work the same way.  For information on the subcom-
     mand, see the csh command.

     The signal system call  in AIX Operating System Technical
     Reference.