Returns nothing if the domain exists and 'No match for domain.com' otherwise.

Renames all the jpg files as their timestamps with ".jpg" extension.

Remove newlines from output.

One character shorter than awk /./ filename and doesn't use a superfluous cat.

To be fair though, I'm pretty sure fraktil was thinking being able to nuke newlines from any command is much more useful than just from one file.

Pipe any output to "grep ." and blank lines will not be printed.

Gets the internal and external IP addresses of all your interfaces, or the ones given as arguments

Will return your internal IP address.

The same as the other user, but smarter, using -d and -f

xargs -P N spawns up to N worker processes. -n 40 means each grep command gets up to 40 file names each on the command line.

This one will work a little better, the regular expressions it is not 100% accurate for XML parsing but it will suffice any XML valid document for sure.

Within /proc and /sys there are a lot of subdirectories, which carry pseudofiles with only one value as content. Instead of cat-ing all single files (which takes quite a time) or do a "cat *" (which makes it hard to find the filename/content relation), just grep recursively for . or use "grep . /blabla/*" (star instead of -r flag).

For better readability you might also want to pipe the output to "column -t -s : ".

The example command deletes all aliases for network interface 'em0' assuming that the aliases have netmask of 255.255.255.255 and the master IP has some other netmask (such as 255.255.255.0). See here -> http://my.galagzee.com/2009/07/22/deleting-all-network-interface-aliases/ for more on the rationale of this command.

Retrieve top ip threats from http://isc.sans.org/sources.html and add them into iptables output chain.

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.

Useful if you f.i. want to block/allow all connections from a certain provider which uses successive netnames for his ip blocks. In this example I used the german Deutsche Telekom which has DTAG-DIAL followed by a number as netname for the dial in pools.

There are - as always ;) - different ways to do this. If you have seq available you can use

or without seq you can use bash brace expansion

or if you like while better than for use something like

and so on.

The command could show you all conecctions if you skip "grep ESTABLISHED"

bnd-ips.txt is a list of IP adresses that is concenated for use as regular expression. Yes, this is still very speedy ;=)

Should work on all systems that use dpkg and APT package management.

Find Word docs by filename in the current directory, convert each of them to plain text using antiword (taking care of spaces in filenames), then grep for a search term in the particular file.

(Of course, it's better to save your data as plain text to make for easier grepping, but that's not always possible.)

Requires antiword. Or you can modify it to use catdoc instead.

This should work anywhere perl and grep is available. :P