or which <command> > /dev/null 2>&1 || echo Error! For example, I write which colordiff > /dev/null 2>&1 && alias diff=colordiff in my `~/.bashrc`.

This is based on the Windows Version of VirtualBox. From the /? ... VBoxManage clonehd | [--format VDI|VMDK|VHD|RAW|] [--variant Standard,Fixed,Split2G,Stream,ESX] [--type normal|writethrough|immutable|shareable] [--remember] [--existing] From the online help.. http://www.virtualbox.org/manual/ch08.html#id2676537 VBoxManage clonehd This command duplicates a registered virtual hard disk image to a new image file with a new unique identifier (UUID). The new image can be transferred to another host system or imported into VirtualBox again using the Virtual Media Manager; see the section called ?The Virtual Media Manager? and the section called ?Cloning disk images?. The syntax is as follows: VBoxManage clonehd | [--format VDI|VMDK|VHD|RAW|] [--variant Standard,Fixed,Split2G,Stream,ESX] [--type normal|writethrough|immutable] [--remember] where the parameters mean: format Allow to choose a file format for the output file different from the file format of the input file. variant Allow to choose a file format variant for the output file. It is a comma-separated list of variant flags. Not all combinations are supported, and specifying inconsistent flags will result in an error message. type Only honored if --remember is also specified. Defines what kind of hard disk type this image should be. remember Keep the destination image registered after it was successfully written. Show Sample Output

when we work with terminal often we open man pages for help if we did some mistakes and when we want to open the man page for command we are working with this one helps as many people may be knowing that '!!' performs the last command action we use it in sudo !! to perform the last action with root previleages man !! will also be helpful and handy thanx

Build an awk array with all commands and then select a random one at the end. This avoids spawning extra processes for counting with wc or generating random numbers. Explicitly call /bin/ls to avoid interactions with aliases.

Allows you to change the value of an environment variable only for the execution of the command in the line. (corrected) Show Sample Output

Only a few characters of the previous command are necessary.

# Small for loop, that can list files in dir, and after that executes # [COMMAND] of your choice, usefull for example rename, move, tar etc.. # change cmd's for different results :)

Show Sample Output

Read all chapters up to 'Jumping', improve your effectiveness of wirking in terminal. Most useful are the Moving and Searching commands

Credit goes to "eightmillion" Show Sample Output

It's hard to beat C. This is just slightly faster than the bc version on my machine. real 0m26.856s user 0m25.030s sys 0m0.024s Requirements: libgmp headers, gcc. Show Sample Output

Work only with bash and apt-file installed. When it found an unknow command, it will search for a file named "scribus" (in my example), in a folder named bin and then install the corresponding package. After installation, it will run the command. Usefull juste after reinstalling linux and missing lot of package. Show Sample Output

Yep, now you can finally google from the command line! Here's a readable version "for your pleasure"(c): google() { # search the web using google from the commandline # syntax: google google query=$(echo "$*" | sed "s:%:%25:g;s:&:%26:g;s:+:%2b:g;s:;:%3b:g;s: :+:g") data=$(wget -qO - "https://ajax.googleapis.com/ajax/services/search/web?v=1.0&q=$query") title=$(echo "$data" | tr '}' '\n' | sed "s/.*,\"titleNoFormatting//;s/\":\"//;s/\",.*//;s/\\u0026/'/g;s/\\\//g;s/#39\;//g;s/'amp;/\&/g" | head -1) url="$(echo "$data" | tr '}' '\n' | sed 's/.*"url":"//;s/".*//' | head -1)" echo "${title}: ${url} | http://www.google.com/search?q=${query}" } Enjoy :) Show Sample Output

A very interesting man page!

This command kills all processes with 'SomeCommand' in the process name. There are other more elegant ways to extract the process names from ps but they are hard to remember and not portable across platforms. Use this command with caution as you could accidentally kill other matching processes! xargs is particularly handy in this case because it makes it easy to feed the process IDs to kill and it also ensures that you don't try to feed too many PIDs to kill at once and overflow the command-line buffer. Note that if you are attempting to kill many thousands of runaway processes at once you should use 'kill -9'. Otherwise the system will try to bring each process into memory before killing it and you could run out of memory. Typically when you want to kill many processes at once it is because you are already in a low memory situation so if you don't 'kill -9' you will make things worse

This decompresses the file and sends the output to STDOUT so it can be grepped. A good one to put in loops for searching directories of gzipped files, such as man pages. Show Sample Output

This works in multiple unixes, not only linux, for different paths. On solaris, if you do not have which, you can use: ksh whence -p anypath/a_command.sh | sed "s|^./|$(pwd)|" ksh whence -p Show Sample Output

I know how hard it is to find an old command running through all the files because you couldn't remember for your life what it was. Heres the solution!! Grep the history for it. depending on how old the command you can head or tail or if you wanted to search all because you cannot think how long ago it was then miss out the middle part of the command. This is a very easy and effective way to find that command you are looking for.

Instead of using: 0,15,30,45 * * * * /path/to/command

Display man page in plain text