This was posted on reddit. replace 192.168.0.1-256 with the IP's you want to check.

This command will sort the contents of FILENAME by redirecting the output to individual .txt files in which 3rd column will be used for sorting. If FILENAME contents are as follows: foo foo A foo bar bar B bar lorem ipsum A lorem Then two files called A.txt and B.txt will be created and their contents will be: A.txt foo foo A foo lorem ipsum A lorem and B.txt will be bar bar B bar

In the above example 'muspi merol' (the output of the first rev command) is sent to stderr and 'lorem ipsum' (the output of the second rev command) is sent to stdout. rev reverse lines of a file or files. This use of tee allows testing if a program correctly handles its input without using files that hold the data. Show Sample Output

This command will copy files and directories from a remote machine to the local one. Ensure you are in the local directory you want to populate with the remote files before running the command. To copy a directory and it's contents, you could: ssh user@host "(cd /path/to/a/directory ; tar cvf - ./targetdir)" | tar xvf - This is especially useful on *nix'es that don't have 'scp' installed by default.

This command will show the 20 processes using the most CPU time (hungriest at the bottom). You can see the 20 most memory intensive processes (hungriest at the bottom) by running: ps aux | sort +3n | tail -20 Or, run both: echo "CPU:" && ps aux | sort +2n | tail -20 && echo "Memory:" && ps aux | sort +3n | tail -20

I find it ugly & sexy at the same time isn't it ?

Empty the trash when the icon stay in the non-empty state source: http://www.linuxquestions.org/blog/phoenixrising-455874/2009/3/3/how-to-empty-trash-in-gnome-when-the-trash-can-refuses-to-clear-1660/

http://en.wikipedia.org/wiki/Year_2038_problem Some other notable dates that have passed: date -d@1234567890 date -d@1000000000 Show Sample Output

rot13 maps a..mn..z (A..MN..Z) to n..za..m (n..za..m) and so does this alias.

create a short alias for 'ls' with multi-column (-C), file type syntax additions (slashes after directories, @ for symlinks, etc... (-F), long format (-l), including hidden directories (all ./, ../, .svn, etc) (-a), show file-system blocks actually in use (-s), human readable file sizes (-h)

Searches /var/log/secure for smtp connections then lists these by number of connections made and hosts.

Searches the /var/log/secure log file for Failed and/or invalid user log in attempts. Show Sample Output

Not so much handy by itself, but very nice in shell scripts. This makes you a handy ncurses based checklist. Much like terminal installers, just use the arrow keys and hit 'Space' to adjust the selections. Returns all selected tags as strings, with no newline at the end. So, your output will be something like: "one" "two" "three" "four" "etc" For those who prefer bash expansion over gratuitious typing: whiptail --checklist "Simple checkbox menu" 12 35 3 $(echo {one,two,three,four}" '' 0"} ) Things to note: The height must includes the outer border and padding: add 7 to however many items you want to show up at the same time. If the status is 1, it will be selected by default. anything else, will be deselected. Show Sample Output

This command will tell you the 20 biggest directories starting from your working directory and skips directories on other filesystems. Useful for resolving disk space issues.

If you need to print some portion of a huge file, let's say you want to print from line 200 to 300, you can use this command to print the line from LINE1 to LINE2 of file FILE.

The pinfo package makes info pages much more bearable. It is a ncurses-based POSIX utility for viewing info and man pages using lynx style keyboard shortcuts and rendering. Links are highlighted blue, the current location of your cursor is red. Navigating and searching are easy. Worth the install.

By time thumbnail images in ~/thumbnails take up too much space, this command will help deleting old ones. Find options explained: -type f : find files only, not directories -atime +30 : last accessed more than 30 days ago

An improved version of http://www.commandlinefu.com/commands/view/1772/simple-countdown-from-a-given-date that uses Perl to pretty-print the output. Note that the GNU-style '--no-title' option has been replaced by its one-letter counterpart '-t'. Show Sample Output

If (when) you forget to "svn rm" files from your repository, use this to let your repository know you want those files gone. Of course this works with adding and reverting too.