All commands

Useful when you forget to use sudo for a command. "!!" grabs the last run command.

I often forget to sudo before editing a file I don't have write permissions on. When you come to save that file and get the infamous "E212: Can't open file for writing", just issue that vim command in order to save the file without the need to save it to a temp file and then copy it back again.

Really useful for when you have a typo in a previous command. Also, arguments default to empty so if you accidentally run:

you can correct it with

mtr combines the functionality of the traceroute and ping programs in a single network diagnostic tool.

As mtr starts, it investigates the network connection between the host mtr runs on and HOSTNAME. by sending packets with purposly low TTLs. It continues to send packets with low TTL, noting the response time of the intervening routers. This allows mtr to print the response percentage and response times of the internet route to HOSTNAME. A sudden increase in packetloss or response time is often an indication of a bad (or simply over‐loaded) link.

!whatever will search your command history and execute the first command that matches 'whatever'. If you don't feel safe doing this put :p on the end to print without executing. Recommended when running as superuser.

To generate the keys use the command ssh-keygen

Next time you are using your shell, try typing ctrl-x e (that is holding control key press x and then e). The shell will take what you've written on the command line thus far and paste it into the editor specified by $EDITOR. Then you can edit at leisure using all the powerful macros and commands of vi, emacs, nano, or whatever.

now you can acces the website by going to http://localhost:2001/

If you bork your terminal by sending binary data to STDOUT or similar, you can get your terminal back using this command rather than killing and restarting the session. Note that you often won't be able to see the characters as you type them.

For when you want to flush all content from a file without removing it (hat-tip to Marc Kilgus).

This is an alternative to cron which allows a one-off task to be scheduled for a certain time.

This will output the sound from your microphone port to the ssh target computer's speaker port. The sound quality is very bad, so you will hear a lot of hissing.

Makes a partition in ram which is useful if you need a temporary working space as read/write access is fast.

Be aware that anything saved in this partition will be gone after your computer is turned off.

Useful for checking if there are differences between local and remote files.

The PID will only be printed if you're holding a root equivalent ID.

Very useful for rerunning a long command changing some arguments globally.

As opposed to ^foo^bar, which only replaces the first occurrence of foo, this one changes every occurrence.

Install SSHFS from http://fuse.sourceforge.net/sshfs.html

Will allow you to mount a folder security over a network.

Particularly useful if you're mounting different drives, using the following command will allow you to see all the filesystems currently mounted on your computer and their respective specs with the added benefit of nice formatting.

-p parameter tells wget to include all files, including images.

-e robots=off you don't want wget to obey by the robots.txt file

-U mozilla as your browsers identity.

--random-wait to let wget chose a random number of seconds to wait, avoid get into black list.

Other Useful wget Parameters:

--limit-rate=20k limits the rate at which it downloads files.

-b continues wget after logging out.

-o $HOME/wget_log.txt logs the output