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 omited 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.
−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. Warning: some of these examples may affect the operation of your system.
Play a random
sound after 4 minutes (perfect for toast):
sleep 240 ; play ’find /sounds −name
’*.au’ −print | rl
−−count=1’
Renice all the
processes of a random logged−in user:
renice +5 −u ’who | cut ’−d ’
−f 1 | sort −u | rl
−−count=1’
Kill a random
process on your computer.
kill −9 ’ps −A | awk ’{print
$1}’ | rl −−count=1’
Do this as root and see how long your system keeps working.
Increase the −−count for extra effect. (you may
need to change the ps and awk parameters depending on your
system)
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.
COPYRIGHT
Copyright
© 2001, 2002, 2003 Arthur de Jong
<arthur [AT] tiefighter.nl>.
This is free software; see the license for copying
conditions. There is NO warranty; not even for
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.