This is useful for sending data between 2 computers that you have shell access to. Uses tar compression during transfer. Files are compressed & uncompressed automatically. Note the trailing dash on the listening side that makes netcat listen to stdin for data.

on the listening side:

explanation: open netcat to -l listen on -p port 2022, take the data stream and pipe to tar -x extract, -v verbose, -f using file filename - means "stdin"

on the sending side:

explanation: compress all files in current dir using tar -c create, -v verbose, -f using file, - filename - here means "stdout" because we're tar -c instead of tar -x, -w3 wait 3 seconds on stream termination and then end the connection to the listening host name_of_listening_host, on port 2022

You can't stand programs x, y, and z. Remove all trace of their existence by adding this function to your config. It will remove the cruft, the settings, and such and such. This function doesn't even give a damn about you trying to remove programs that don't exist: it'll just for loop to the next one on your hit list.

when we add a new package to a aptitude (the debian package manager) we need to add the gpg, otherwise it will show warning / error for missing key

when we add a new package to a aptitude (the debian package manager) we need to add the gpg, otherwise it will show warning / error for missing key

Show the number of failed tries of login per account. If the user does not exist it is marked with *.

from http://maysayadkaba.blogspot.com/2008/08/linux-check-ram-speed-and-type.html

List all process running a specfic port

This will get the job done in the most efficient way -

spawning only one `rm` process.

"On-the-fly" find data is displayed through `tee` and

you should have plenty of time to ctrl-c if needed before it's too late.

You may need to re-run this after major Software Updates.

To leave more languages in, add more ``-and \! -iname "lang*"'' statements:

**Edit: note the 2nd sudo near the end of the pipeline - this is necessary.

This command lets you see and scroll through all of the strings that are stored in the RAM at any given time. Press space bar to scroll through to see more pages (or use the arrow keys etc).

Sometimes if you don't save that file that you were working on or want to get back something you closed it can be found floating around in here!

The awk command only shows lines that are longer than 20 characters (to avoid seeing lots of junk that probably isn't "human readable").

If you want to dump the whole thing to a file replace the final '| less' with '> memorydump'. This is great for searching through many times (and with the added bonus that it doesn't overwrite any memory...).

Here's a neat example to show up conversations that were had in pidgin (will probably work after it has been closed)...

(depending on sudo settings it might be best to run

first to get to a # prompt)

only for sudo-style systems.

Use this construct instead of I/O re-directors ``>'' or ``>>'' because

sudo only elevates the commands and *not* the re-directors.

***warning: remember that the `tee` command will clobber

file contents unless it is given the ``-a'' argument

Also, for extra security, the "left" command is still run unprivileged.

Discovering all executables on your system that can be run as another user, especially root, is critical for system security. The above command will find those files with have SUID or SGID bits set and are owned by the root user or group.

Useful mainly for debugging or troubleshooting an application or system, such as X11, Apache, Bind, DHCP and others. Another useful switch that can be combined with -mmin, -mtime and so forth is -daystart. For example, to find files that were modified in the /etc directory only yesterday:

Saved my day, when my harddrive got stuck in read-only mode.

This will create an exact duplicate image of your hard drive that you can then restore by simply reversing the "if" & "of" locations.

Alternatively, you can use an SSH connection to do your backups:

Add the functions to the .bashrc to make it work

Example: First go to the iso file directory and type:

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[email protected]:~$ miso file.iso

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It will put you into a temporary mounting point directory (ISO_CD) and will show the files

You can umount the iso file whatever the directory you are

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[email protected]:~/ISO_CD$ uiso

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It wil umount the iso file and remove the temporary directory in your home

I often forget to type sudo before a command that needs it. This is the quickest way to rerun the command prefixed by sudo.

Someone might attack on your system. You can drop attacker IP using IPtables. However, you can use route command to null route unwanted traffic. A null route (also called as blackhole route) is a network route or kernel routing table entry that goes nowhere. Matching packets are dropped (ignored) rather than forwarded, acting as a kind of very limited firewall. The act of using null routes is often called blackhole filtering.

An apt-get wrapper function which will run the command via sudo, but will run it normally if you're only downloading source files.

This was a bit of an excuse to show off the framework of

...but as you can see, you must be careful about what is in the "true" block to make sure it executes without error, otherwise the "false" block will be executed.

To allow the apt-get return code to pass through, you need to use a more normal if/else block:

This will give you the Dell Service tag number associated with your machine. Incredibly useful when you need that number for tech support or downloads.

List the commands you have the right to use with sudo.

Opens a new shell as root. Useful if you want to run a lot of commands as superuser without needing to sudo each of them.