how can i redirect standard input? i dont remember :/, though could you redirec not from a command? i mean, to redirect always stdin and stout (1 Reply)
I tried copy the output files from find command into a directory.
Example,
find / -name core 2>/dev/null | xargs cp????
I have known that we can use xargs to execute command lines from standard input but how to use it in this case.
Or I can do something besides xargs. (2 Replies)
Dear...
I have a scrpit that contains multiple read command.... when I run the script I have to enter 3 variables so that I can get the output..
but, I dont want to put those 3 inputs manually every time... I want to make a shell that reads the 3 inputs from a file.
the script name is... (4 Replies)
Hi guys,
I am new to AWK and unix scripting. Please see below my problem and let me know if anyone you can help.
I have 2 input files (example given below)
Input file 2 is a standard file (it will not change) and we have to get the name (second column after comma) from it and append it... (5 Replies)
Hello,
Could somebody please give me an awk example on how to read from the standard input.
It means as the "read" function in Korn shell.
Thx in advance ... (3 Replies)
Is it possible to read from the screen or standard output? If so, may I know how I can do this?
For example, I have an application running which prints out the following on the screen:
Starting tools from .image-tools...
imagecontrol_1: SECS/GEM-capable version is running
done
cindy@pgunix... (2 Replies)
So, I am new to shell scripting and have a few problems.
I know how to read from standard input but I do not know how to really compare it to say, a character. I am trying to compare it to a character and anything exceeding just a character, the user will get an output message, but the program... (7 Replies)
I have a program that requires the user to enter input values while it is being run
for example in bash
...
...
..
echo "Enter your input"
read input
echo $input
...
...
...I need to schedule this program with crontab, hence a problem, cronjobs run in the background, any ideas on how to... (10 Replies)
Just started learning Unix and received my first assignment recently. We haven't learned many commands and honestly, I'm stumped. I'd like to receive assistance/guidance/hints.
1. The problem statement, all variables and given/known data:
How do I write a shell script that takes in a file or... (4 Replies)
Discussion started by: fozilla
4 Replies
LEARN ABOUT REDHAT
rl
rl(1) User Commands rl(1)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='
' 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 (C) 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.
Version 0.2.7 Jul 2008 rl(1)