NAME
       loop - syntactic sugar for commandline loops


SYNOPSIS
       loop [-cfhrv] [-d seconds] [-i iterations] command


DESCRIPTION
       The  loop  utility  eases the creation of common commandline loops
       one would  usually  build  upon  while  or  for.   It's  primarily
       designed  to  reduce  the number of keystrokes during a shell ses‐
       sion.


OPTIONS
       -c, -C Enables (-c) or disables  (-C)  clear(1)  mode,  where  the
              screen  is  cleared every single iteration, before the com‐
              mand is executed.

       -d seconds, -D
              Enables or disables delay mode. In this  mode,  after  each
              execution  of  command,  the script is paused for the given
              number of seconds.

       -f, -F Enables or disables failure ignore mode. In this mode,  the
              loop will continue even if the command exits with a failure
              status.

       -h, -H Print a short help message on STDOUT or STDERR and exit.

       -i iterations, -I
              Enables or disables iteration limit mode. In this mode, the
              loop will be aborted after the given number of iterations -
              unless another break condition has occured before.

       -r, -R Enables or disables readline mode. In this mode,  the  loop
              will  invoke  the  read(1)  command for every iteration and
              export the  content  in  the  $LINE  environment  variable.
              Execition is stopped as soon as EOF is encountered.

       -v, -V Enables or disables verbose mode.


COMMANDS
       The  command  may be any shell command applicable. One should note
       the common pitfalls with shell escaping, such as the fact that the
       exported  $LINE  and $ITER variables have to be escaped and, e.g.,
       stream redirection can get a bit tricky. The easiest  way  to  get
       around this is usually to simply put the command in quotes.


EXAMPLES
       # Print "Hello World!" twice
       loop -i 2 echo Hello World!

       # Clear screen, run phpunit(1), ignore failures but do not start over
       # until RETURN is pressed
       loop -fc phpunit --wait --colors MyTestCase.php

       # Display the source of loop(1), one line per second, enumerated
       loop -rd 1 'echo "`printf %3d $ITER` $LINE"' < `which loop`


ENVIRONMENT VARIABLES
       The  loop  utility does not need any setup. However, it's possible
       to assign a default for the most common options:

       LOOP_CLEAR
              Corresponds to the -c option; if nonempty, loop will be  in
              clear(1) mode by default. Can be overridden with -C.

       LOOP_IGNORE_FAILURES
              Corresponds to the -f option; if nonempty, loop will ignore
              failures by default. Can be overridden with -F.

       LOOP_VERBOSE
              Corresponds to the -v option; if nonempty, loop will create
              verbose output by default. Can be overriden with -V.


BUGS
       Probably infinite.


SEE ALSO
       clear(1), getopt(1), sh(1)


COPYING
       Mathias  J. Hennig wrote this script and it's manual page. As long
       as you retain this notice you can do whatever you want  with  this
       stuff.  If we meet some day, and you think this stuff is worth it,
       you can buy me a beer in return.