Commands using grep (1,935)

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Change the default editor for modifying the sudoers list.
On Ubuntu, the default editor for visudo is nano. To change the editor to something else (e.g., vi) use this command.

Terminal - Prints out, what the users name, notifyed in the gecos field, is

See multiple progress bars at once for multiple pipes with pv
In this example we convert a .tar.bz2 file to a .tar.gz file. If you don't have Pipe Viewer, you'll have to download it via apt-get install pv, etc.

Opens vi/vim at pattern in file
Open up vi or vim at the first instance of a pattern in [file]. Useful if you know where you want to be, like "PermitRootLogin" in sshd_config. Also, vi +10 [file] will open up a file at line 10. VERY useful when you get "error at line 10" type of output.

Gets directory and files tree listing from a FTP-server
Creates a file with contents like `du -a`, only it is remote server filesystem hierarchy. Very usefull then for grep-ing without remote connection.

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Get the total length of all videos in the current dir in H:m:s
You're behind on your TV catch-up, but how far behind? This command tries to open mplayer against all files in the current dir. If it's a video file it will contain ID_LENGTH, which is summed and output in hours, minutes and seconds. Someone better at awk could probably reduce this down a lot.

Remove all zero size files from current directory (not recursive)

Find out how old a web page is
I used to use the Firefox "View page info" feature a lot to determine how stale the web page I was looking at was. Now that I use mostly Chrome I miss that feature, so here is a command line alternative using wget. The -S says to display the server response, the --spider says to not download any files/pages, just fetch the header. The output goes to stderr, so to grep it you use 2>&1 to combine the stderr stream with stdout, the pipe that to grep for Last-Modified. You can use curl instead if you have it installed, like this: $ curl --head -s http://osswin.sourceforge.net | grep Mod

Get Cookies from bash
The loop is to compare cookies. You can remove it... Maybe you wanna use curl... $ curl www.commandlinefu.com/index.php -s0 -I | grep "Set-Cookie"


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