You can use [n]> combined with >(cmd) to attach the various output file descriptors to be the input of different commands.
This is shorter and actually much faster than >/dev/null (see sample output for timings) Plus, it looks like a disappointed face emoticon. Show Sample Output
You have a script where =ALL= STDERR should be redirected to STDIN and you don't want to add "2>&1" at the end of each command...
E.G.:
ls -al /foo/bar 2>&1
Than just add this piece of code at the beginning of your script!
I hope this can help someone. :)
Connect-back shell using Bash built-ins. Useful in a web app penetration test, if it's the case of a locked down environment, without the need for file uploads or a writable directory. -- /dev/tcp and /dev/udb redirects must be enabled at compile time in Bash. Most Linux distros enable this feature by default but at least Debian is known to disable it. -- http://labs.neohapsis.com/2008/04/17/connect-back-shell-literally/
I've had a horrible time trying to pipe the output of some shell built-ins like 'time' to other programs. The built-in doesn't output to stdout or stderr most of the time but using the above will let you pipe the output to something else. Show Sample Output
{ ... } vs ( ... ) reduces the process count, I believe. Typically, I use this logic to redirect a series of commands to a pipe -- { command1 args1 ; command2 args2}|less -- or file -- { command1 args1 ; command2 args2}>foo -- or to spawn the series as a background process -- { ... } & .
Like what it says. Show Sample Output
Ummmm.. Saw that gem on some dead-head hippies VW bus at phish this summer.. It's actually one of my favorite ways of using bash, very clean. It shows what you can do with the cool advanced features like job control, redirection, combining commands that don't wait for each other, and the thing I like the most is the use of the ( ) to make this process heirarchy below, which comes in very handy when using fifos for adding optimization to your scripts or commands with similar acrobatics. F UID PID PPID WCHAN RSS PSR CMD 1 gplovr 30667 1 wait 1324 1 -bash 0 gplovr 30672 30667 - 516 3 \_ sleep 3 1 gplovr 30669 1 wait 1324 1 -bash 0 gplovr 30673 30669 - 516 0 \_ sleep 5 1 gplovr 30671 1 wait 1324 1 -bash 0 gplovr 30674 30671 - 516 1 \_ sleep 7 Show Sample Output
Useful for situations where you have word lists or dictionaries that range from hundreds of megabytes to several gigabytes in size. Replace file.lst with your wordlist, replace 50000 with however many lines you want the resulting list to be in total. The result will be redirected to output.txt in the current working directory. It may be helpful to run wc -l file.lst to find out how many lines the word list is first, then divide that in half to figure out what value to put for the head -n part of the command.
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