This command delete all the empty lines (include the lines with space) from a file.

g = global command

\S = non-whitespace character; !\S the opposite

d = delete a range

The same as typing 'less filename' then 'G' or '>' or the END key. Comes in handy with shell scripts or aliases:

alias weblog='less +G /var/log/httpd/access_log'

alias errlog='less +G /var/log/httpd/error_log'

Needed to get the Mac of various devices on a solaris box, but didn't have root. This command used awk to display the Network device, the IP, and the MAC a line at a time.

opens a "hidden" remote shell (login will not appear in "last" for example).

This is not really hidden, because the login will be shown in auth.log and the process is visible anyways.

ssh -T = Disable pseudo-tty allocation.

bash -i = interactive shell

You can use multiple field separators by separating them with | (=or).

This may be helpful when you want to split a string by two separators for example.

#echo "one=two three" | awk -F "=| " {'print $1, $3'}

one three

Place the line above in your ~/.bahsrc file. Now every time you issue the 'vb' command, you invoke the vim editor to edit it, then source it so the changes take effect immediately.

Notes:

* This mechanism is not working well if your .bashrc contains commands that should not be sourced more than once.

* This trick also work for your csh or tclsh users: place the following line in your ~/.cshrc file:

alias vc 'vim ~/.cshrc; source ~/.cshrc

Thank you adzap for pointing out the missing quote

On command mode in Vim you can save parts of the current buffer in another file.

* The 'n' value represents the first line of the new file.

* The 'm' value represents the last line of the new file.

* newfile.txt is the newfile.

The results are similar to this command in perl:

Immediately after installing things into your PATH (e.g. under /usr/bin), currently open shells cannot find them ("zsh: command not found"). Use rehash to get the shell to rescan available executables.

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.

Very useful when you need disk space. It calculates the disk usage of all files and dirs (descending them) located at the current directory (including hidden ones). Then sort puts them in order.

Just waste some resources in a philosophical way

To connect to the shell run:

Launch a command from within a manpage, vim style. This is rather trivial, but can be very useful to try out the functions described in a manpage without actually quitting it (or switching to another console/screen/...).

Rather than typing out all 10 files, you can use brace expansion to do the trick for you. This is useful for backup files, numbered files, or any files with a repeating pattern. Gives more control than 'rm file*' as I might want to keep others around.

When downloading RPMs from the Internet, you don't have to 'rpm -i' or 'rpm -U' to install the package. Especially, if the package has dependencies. If you have YUM setup to access an RPM repository, this command will install the downloaded package, then any dependencies through YUM that it relies on. Very handy on RPM-based systems.

In this case, I'm keeping an eye on /var/log/messages, but of course any file will do. When I'm following a file, I generally don't want to see anything other than what has been added due to the command or service I've executed. This keeps everything clean and tidy for troubleshooting.

Useful to e.g. keep an eye on several logfiles.

It displays, last 15 yum operations (in last operation as first row order) with its dates. Change 15 to any number of operations you need to display or remove "| tac" to see it in reverse order (last operation as last row)

This will play the audio goodness posted up on PlayTweets via twitter right form the ever loving cmdline. You do not even need a twitter account. I hashed this out in a bit of a hurray as the kids need to get to sleep....I will be adding a loop based feature that will play new items as they come in...after what your are listening to is over.

http://twitter.com/playTweets for more info on playtweets

Generated the CPU utilization stats with 5 lines /every 2 seconds.

Needs sysstat package to be installed prior to use sar.