The sort utility is well used, but sometimes you want a little chaos. This will randomize the lines of a text file.

BTW, on OS X there is no

option! There is also no

These are only in the newer GNU core...

This is also faster than the alternate of:

If the connection works you should see a "hello" on host A. If not: check your cabeling etc :-)

cat -n file : number all line

cat -b file : number only non empty line

see man cat

uuencode the file to appear as an attachment

This just reads in a local file and sends it via email. Works with text or binary. *Requires* local mail server.

This helped me find a botnet that had made into my system. Of course, this is not a foolproof or guarantied way to find all of them or even most of them. But it helped me find it.

Using OpenSSL we can encrypt any input we wish and then use Netcat to create a socket which can be connected to from an externally source (even using a Web Browser)

This will diff your local version of the file with the latest version in svn. I put this in a shell function like so:

middlehost allows ssh access from where you are but not securehost.

Use nice ssh piping to simulate scp through A => B => C

setting up the shell function if left as an exercise for the reader. ;-)

Agent forwarding should avoid password typing.

Uses the data in the /proc system, provided by the acpid, to find out the CPU temperature. Can be run on systems without lm-sensors installed as well.

du only accepts lines ending with a NUL, which can be a pain to create. This solves that issue.

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

If you want certain files out of a directory hierarchy, this will copy just the listed files, but will create the directory hierarchy in the new location ($DIR/)

Plays the sound of the file, should sound like *some* kind of music, most files sound like static but some are really cool.

variations:

Check out http://bbs.archlinux.org/viewtopic.php?id=70937 for more variations!

semi-dupe--like http://www.commandlinefu.com/commands/view/985/generate-white-noise but with different syntax and program.

Easy way to find out what Debian version your machine is running

If you are downloading a big file (or even a small one) and the connection breaks or times out, use this command in order to RESUME the download where it failed, instead of having to start downloading from the beginning. This is a real win for downloading debian ISO images over a buggy DSL modem.

Take the partially downloaded file and cat it into the STDIN of curl, as shown. Then use the "-C -" option followed by the URL of the file you were originally downloading.

This is an extract from a larger script which formats the video for DVD. The videos I use have no audio track so I need to add one. Tweak as you like...

use find to grep all .c files from the target directory, cat them into one stream, then piped to wc to count the lines

The command `cat file >> file` failes with the following error message:

cat: file: input file is output file

`tee` is a nice workaround without using any temporary files.