All commands

time read -sn1 (s:silent, n:number of characters. Press any character to stop)

Unreachable_host is unavailable from local network, but it's available from reachable_host's network. This command creates a connection to unreachable_host through "hidden" connection to reachable_host.

Example :

## damn

## like a boss.

Example 2 :

##uh... autocomplete doesn't work...

##ah! that's the name of the file!

This will issue a shutdown command to the Windows machine. username must be an administrator on the Windows machine. Requires samba-common package installed. Other relevant commands are:

net rpc shutdown -r : reboot the Windows machine

net rpc abortshutdown : abort shutdown of the Windows machine

Type:

net rpc

to show all relevant commands

Using +F will put less in follow mode. This works similar to 'tail -f'. To stop scrolling, use the interrupt. Then you'll get the normal benefits of less (scroll, etc.).

Pressing SHIFT-F will resume the 'tailling'.

Use Ctrl-] to stop it.

notice what happens when there is more than one unread message in a thread...

also people please dont hardcode the password when you use curl. Leave it out and curl will ask you when it runs. Please...?

This will output the characters at 10 per second.

If the machine is hanging and the only help would be the power button, this key-combination will help to reboot your machine (more or less) gracefully.

R - gives back control of the keyboard

S - issues a sync

E - sends all processes but init the term singal

I - sends all processes but init the kill signal

U - mounts all filesystem ro to prevent a fsck at reboot

B - reboots the system

Save your file before trying this out, this will reboot your machine without warning!

http://en.wikipedia.org/wiki/Magic_SysRq_key

Waiting for your server to finish rebooting? Issue the command above and you will hear a beep when it comes online. The -i 60 flag tells ping to wait for 60 seconds between ping, putting less strain on your system. Vary it to your need. The -a flag tells ping to include an audible bell in the output when a package is received (that is, when your server comes online).

ps returns all running processes which are then sorted by the 4th field in numerical order and the top 10 are sent to STDOUT.

Easy and direct way to find this out.

I find this terribly useful for grepping through a file, looking for just a block of text. There's "grep -A # pattern file.txt" to see a specific number of lines following your pattern, but what if you want to see the whole block? Say, the output of "dmidecode" (as root):

Will show me everything following the battery block up to the next block of text. Again, I find this extremely useful when I want to see whole blocks of text based on a pattern, and I don't care to see the rest of the data in output. This could be used against the '/etc/securetty/user' file on Unix to find the block of a specific user. It could be used against VirtualHosts or Directories on Apache to find specific definitions. The scenarios go on for any text formatted in a block fashion. Very handy.

CDPATH tells the cd command to look in this colon-separated list of directories for your destination. My preferred order are 1) the current directory, specified by the empty string between the = and the first colon, 2) the parent directory (so that I can cd lib instead of cd ../lib), 3) my home directory, and 4) my ~/projects directory.

If are a Bash user and you are in a directory and need to go else where for a while but don't want to lose where you were, use pushd instead of cd.

cd /home/complicated/path/.I/dont/want/to/forget

pushd /tmp

cd thing/in/tmp

popd (returns you to /home/complicated/path/.I/dont/want/to/forget)

A nice way to use the console in full screen without forget the current time.

you can too add other infos like cpu and mem use.

This is a simple example of using proper command nesting using $() over ``. There are a number of advantages of $() over backticks. First, they can be easily nested without escapes:

versus

Second, they're easier to read, then trying to decipher the difference between the backtick and the singlequote: `'. The only drawback $() suffers from is lack of total portability. If your script must be portable to the archaic Bourne shell, or old versions of the C-shell or Korn shell, then backticks are appropriate, otherwise, we should all get into the habit of $(). Your future script maintainers will thank you for producing cleaner code.

Sometimes commands are long, but useful, so it's helpful to be able to make them permanent without having to retype them. An alternative could use the history command, and a cut/sed line that works on your platform.

bash/ksh subshell redirection (as file descriptors) used as input to diff