This will comment out a line, specified by line number, in a given file.

I needed a way to search all files in a web directory that contained a certain string, and replace that string with another string. In the example, I am searching for "askapache" and replacing that string with "htaccess". I wanted this to happen as a cron job, and it was important that this happened as fast as possible while at the same time not hogging the CPU since the machine is a server.

So this script uses the nice command to run the sh shell with the command, which makes the whole thing run with priority 19, meaning it won't hog CPU processing. And the -P5 option to the xargs command means it will run 5 separate grep and sed processes simultaneously, so this is much much faster than running a single grep or sed. You may want to do -P0 which is unlimited if you aren't worried about too many processes or if you don't have to deal with process killers in the bg.

Also, the -m1 command to grep means stop grepping this file for matches after the first match, which also saves time.

Uses curl to download page of membership of US Congress. Use sed to strip HTML then perl to print a line starting with two tabs (a line with a representative)

Assuming that $script contains the filename of a script you'd like to post as part of a comment on this site, this will prefix each line with '$' and pipe it into the X selection. From there just put the cursor in the right place in the comments box and middle-click.

Should work pretty much anywhere with xclip installed. On debian-ish systems this is installed as part of the package "xclip".

Checks the Gmail ATOM feed for your account, parses it and outputs a list of unread messages.

For some reason sed gets stuck on OS X, so here's a Perl version for the Mac:

If you want to see the name of the last person, who added a message to the conversation, change the greediness of the operators like this:

Manages everything through one sed script instead of pipes of greps and awks. Quoting of shell variables is generally easier within a sed script.

Based on the MrMerry one, just add some visuals to differentiate files and directories

Based on the MrMerry one, just add some visuals and sort directory and files

saves one command. Needs GNU grep though :-(

The grep switches eliminate the need for awk and sed. Modifying vim with -p will show all files in separate tabs, -o in separate vim windows. Just wish it didn't hose my terminal once I exit vim!!

This will drop you into vim to edit all files that contain your grep string.

"&&" runs sed if and only if the backup completed and /bin/cp exited cleanly. Works for multiple files; just specify multiple filenames (or glob). Use -v switch for cp to play it safe.

Reverse DNS lookups, from a file with list of IP's, here the file is called lookups.txt

The coolest way I've found to backup a wordpress mysql database using encryption, and using local variables created directly from the wp-config.php file so that you don't have to type them- which would allow someone sniffing your terminal or viewing your shell history to see your info.

I use a variation of this for my servers that have hundreds of wordpress installs and databases by using a find command for the wp-config.php file and passing that through xargs to my function.

Having to escape forwardslashes when using sed can be a pain. However, it's possible to instead of using / as the separator to use : .

I found this by trying to substitute $PWD into my pattern, like so

Of course, $PWD will expand to a character string that begins with a / , which will make sed spit out an error such as "sed: -e expression #1, char 8: unknown option to `s'".

So simply changing it to

did the trick.

I wanted all the 'hidden' .flv files from the http link in the command line; wget seemed appropriate, fed with output from lynx, grep the flv files and the normalised via sed (to remove the numeric bullet). Similar to the 'Grab mp3 files' fu. Replace link with your own, grep arg with something more interesting ;) See here for something along the same lines...

http://www.commandlinefu.com/commands/view/1006/grab-mp3-files-from-your-favorite-netcasts-mp3blog-or-sites-that-often-have-good-mp3s

Hope you find it useful! Improvements welcome, naturally.

Strangely enough, there is no option --lines=[negative] with tail, like the head's one, so we have to use sed, which is very short and clear, you see.

Strangely more enough, skipping lines at the bottom with sed is not short nor clear. From Sed one liner :

# delete the last 10 lines of a file

$ sed -e :a -e '$d;N;2,10ba' -e 'P;D' # method 1

$ sed -n -e :a -e '1,10!{P;N;D;};N;ba' # method 2