Advancing with the terminal

Advancing with the terminal

In the previous post we discussed about the basics of the terminal. In this post I will tell you about advanced commands that can be used in the terminal.

System Information Commands:

These commands are used to know information about the system. 

•     df:      The df command displays file system usage for all the mounted partitions.

df –h produces a more readable output in Megabytes (M) and Gigabytes (G). [-h means human-readable].

• ¨    du :  The ducommand displays the disk usage for a directory. For more readable output you can use du –sh.

• ¨    free : The  freecommand displays the free and used memory in the system.

Free –m will give the output in Megabytes which is more readable.

• ¨    top : The topcommand  displays information on your Linux system, running processes and system resources, including CPU, RAM & swap usage and total number of tasks being run. To quit it you can press “q”.

• ¨    uname –a : The unamecommand prints all system information, including machine name, kernel name and version, and a few other details.

• ¨    lsb_release –a : The lsb_release command prints version information for the Linux release you're running.

PASTING IN TERMINAL:

If you tried copying commands and pasting in terminal using ctrl+c and ctrl+vyou might have noticed that pasting won’t work using ctrl+v. To paste into a terminal you can use ctrl+shift+v.

You can also do Middle Button Click on your mouse (both buttons simultaneously on a two-button mouse).

You can also right-click and select paste from the menu.

TERMINAL SHORTCUTS:

Up Arrow or CTRL+P	Scrolls through the commands that you've entered previously.
Down Arrow or ctrl+n	Takes you back to a more recent command.
Enter	When you have the command you want.
Tab	It autocompletes any commands or filenames, if there's only one option, or else gives you a list of options.
ctrl+r	Searches for commands you've already typed. When you have entered a very long, complex command and need to repeat it, using this key combination and then typing a portion of the command will search through your command history. When you find it, simply press Enter.
history	The history command shows a very long list of commands that you have typed previously. Each command is displayed next to a number. You can type !x to execute a previously typed command from the list (replace the X with a number). If you history output is too long, then you can use history | less for a scrollable list.

ctrl+a or Home	Moves the cursor to the start of a line.
ctrl+e or End	Moves the cursor to the end of a line.
esc+b	Moves to the beginning of the previous or current word.
ctrl+k	Deletes from the current cursor position to the end of the line.
ctrl+u	Deletes from the start of the line to the current cursor position.
ctrl+w	Deletes the word before the cursor.
alt+b	Goes back one word at a time.
alt+f	Moves forward one word at a time.
alt+c	Capitalizes letter where cursor is and moves to end of word.

Incremental history searching

This is a very useful feature. Many agree that this is the most useful terminal tool saves you a lot of typing/memorizing. This tool is like the autocomplete feature for the terminal but this is for only previously entered commands.

To use this tool follow these instructions.

Open a terminal and type:

gedit  ~/.inputrc

Then copy and paste the following:

"\e[A": history-search-backward

"\e[B": history-search-forward

"\e[C": forward-char

"\e[D": backward-char

And save. While entering a command just type the first two or three letters and press up arrow and it will complete the command for you!