Tested in bash4

Lists all installed kernels minus the current one. This is useful to uninstall older kernels that take too much space on /boot partition.

My firefox overheats my cpu, sometimes above 90 degrees Celsius ( hence the name? ) To keep an eye on temperature, I put this command inside KAlarm ( a kind of cron) to be repeated every minute, for 5 seconds, color red ( default for osd_cat). Its pretty, ultra small, displays a micro 2 lines text on every desktop and over everything and do not steal focus or interrupt any task. I get the information passively, in the low profile bottom of the screen. Of course you can use it inside a terminal. Just do it: watch -n 60 'acpi -t | osd_cat -p bottom'

Overwrites the boot sector. Since this doesn't overwrite any data, you can usually recover by re-creating the partition table exactly the same as before you zeroed it. This can also help sometimes if you install a new drive in a Windows machine which can't read it.

Hold ctrl and press z to pause the current thread. Run $fg to resume it.

Thanks to flatcap for optimizing this command. This command takes advantage of the ext4 filesystem's resistance to fragmentation. By using this command, files that were previously fragmented will be copied / deleted / pasted essentially giving the filesystem another chance at saving the file contiguously. ( unlike FAT / NTFS, the *nix filesystem always try to save a file without fragmenting it ) My command only effects the home directory and only those files with your R/W (read / write ) permissions. There are two issues with this command: 1. it really won't help, it works, but linux doesn't suffer much (if any ) fragmentation and even fragmented files have fast I/O 2. it doesn't discriminate between fragmented and non-fragmented files, so a large ~/ directory with no fragments will take almost as long as an equally sized fragmented ~/ directory The benefits i managed to work into the command: 1. it only defragments files under 16mb, because a large file with fragments isn't as noticeable as a small file that's fragmented, and copy/ delete/ paste of large files would take too long 2. it gives a nice countdown in the terminal so you know how far how much progress is being made and just like other defragmenters you can stop at any time ( use ctrl+c ) 3. fast! i can defrag my ~/ directory in 11 seconds thanks to the ramdrive powering the command's temporary storage bottom line: 1. its only an experiment, safe ( i've used it several times for testing ), but probably not very effective ( unless you somehow have a fragmentation problem on linux ). might be a placebo for recent windows converts looking for a defrag utility on linux and won't accept no for an answer 2. it's my first commandlinefu command

Creates one letter folders in the current directory and moves files with corresponding initial in the folder.

Mirror a remote directory using some tricks to maximize network speed. lftp:: coolest file transfer tool ever -u: username and password (pwd is merely a placeholder if you have ~/.ssh/id_rsa) -e: execute internal lftp commands set sftp:connect-program: use some specific command instead of plain ssh ssh:: -a -x -T: disable useless things -c arcfour: use the most efficient cipher specification -o Compression=no: disable compression to save CPU mirror: copy remote dir subtree to local dir -v: be verbose (cool progress bar and speed meter, one for each file in parallel) -c: continue interrupted file transfers if possible --loop: repeat mirror until no differences found --use-pget-n=3: transfer each file with 3 independent parallel TCP connections -P 2: transfer 2 files in parallel (totalling 6 TCP connections) sftp://remotehost:22: use sftp protocol on port 22 (you can give any other port if appropriate) You can play with values for --use-pget-n and/or -P to achieve maximum speed depending on the particular network. If the files are compressible removing "-o Compression=n" can be beneficial. Better create an alias for the command.

This command is more for demonstrating piping to vim and jumping to a specific line than anything else. Exit vim with :q! +23 jumps to line 23 - make vim receive the data from the pipe

Create a encrypted tar.gz file from a directory on the fly. The encryption is done by GPG with a public key. The resulting filename is tagged with the date of creation. Very usefull for encrypted snapshots of folders.