NAME

       rl - Randomize Lines.

SYNOPSIS

       rl [OPTION]...  [FILE]...

DESCRIPTION

       rl  reads  lines  from a input file or stdin, randomizes the lines and outputs a specified
       number of lines.  It does this with only a single pass over the input while trying to  use
       as little memory as possible.

       -c, --count=N
              Select  the  number  of  lines  to  be returned in the output.  If this argument is
              omitted all the lines in the file will be returned in random order.  If  the  input
              contains less lines than specified and the --reselect option below is not specified
              a warning is printed and all lines are returned in random order.

       -r, --reselect
              When using this option a single line may be selected multiple times.   The  default
              behaviour  is that any input line will only be selected once.  This option makes it
              possible to specify a --count option with more lines than the file actually holds.

       -o, --output=FILE
              Send randomized lines to FILE instead of stdout.

       -d, --delimiter=DELIM
              Use specified character as a "line" delimiter instead of the newline character.

       -0, --null
              Input lines are terminated by a null character.  This option is useful  to  process
              the output of the GNU find -print0 option.

       -n, --line-number
              Output lines are numbered with the line number from the input file.

       -q, --quiet, --silent
              Be quiet about any errors or warnings.

       -h, --help
              Show short summary of options.

       -v, --version
              Show version of program.

EXAMPLES

       Some simple demonstrations of how rl can help you do everyday tasks.

       Play a random sound after 4 minutes (perfect for toast):
           sleep 240 ; play `find /sounds -name ´*.au´ -print | rl --count=1`

       Play the 15 most recent .mp3 files in random order.
           ls -c *.mp3 | head -n 15 | rl  | xargs --delimiter=´\n´ play

       Roll a dice:
           seq 6 | rl --count 2

       Roll a dice 1000 times and see which number comes up more often:
           seq 6 | rl --reselect --count 1000 | sort | uniq -c | sort -n

       Shuffle the words of a sentence:
           echo -n "The rain in Spain stays mainly in the plain." \
             | rl --delimiter=´ ´;echo

       Find all movies and play them in random order.
           find . -name ´*.avi´ -print0 | rl -0 | xargs -n 1 -0 mplayer
       Because  -0  is used filenames with spaces (even newlines and other unusual characters) in
       them work.

BUGS

       The program currently does not have very smart memory management.  If  you  feed  it  huge
       files  and  expect  it  to  fully  randomize all lines it will completely read the file in
       memory. If you specify the --count option it will only use the memory required for storing
       the specified number of lines.  Improvements on this area are on the TODO list.

       The  program  uses  the  rand()  system  random  function.  This function returns a number
       between 0 and RAND_MAX, which may not be very large on some systems.  This will result  in
       non-random results for files containing more lines than RAND_MAX.

       Note  that  if  you  specify multiple input files they are randomized per file.  This is a
       different result from when you cat all the files and pipe the result into rl.

COPYRIGHT

       Copyright © 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 Arthur de Jong.
       This is free software; see the license for copying conditions.  There is NO warranty;  not
       even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.