Tag: echo

Linux Commands


My daily task list says that I need to learn a new linux command everyday and add it to my blog. Hope I update this post frequently.

Command: echo
What it does: prints a string

Example

bios@bios-11:~$ echo 'hello world!'
hello world!
bios@bios-11:~$ echo -e 'hello world!\n'
hello world!

bios@bios-11:~$ echo -e 'hello\tworld!'
hello	world!

It is evident from code given that -e enables interpretation of escape sequences which by default is not active.

Command: ls
What it does: lists the contents of the current directory

ls -a displays all contents including hidden files

ls -l displays all contents in the lonlisting format.

Example

bios@bios-11:~/vishnu$ ls
byte_of_python_v192.pdf  google                                MIT OCW   python.org & mercurial tutorials  Resume.pdf
cluster maps             google.odt                            moderncv  python programming pdfs           Win XP.vdi
clustr_map.jpg           Linux Complete Command Reference.pdf  progs     rawr.jpg
bios@bios-11:~/vishnu$ ls -a
.                        cluster maps    google.odt                            moderncv                          python programming pdfs  Win XP.vdi
..                       clustr_map.jpg  Linux Complete Command Reference.pdf  progs                             rawr.jpg
byte_of_python_v192.pdf  google          MIT OCW                               python.org & mercurial tutorials  Resume.pdf
bios@bios-11:~/vishnu$ ls -l
total 6690232</pre>
<ul>
	<li>rw-r--r-- 1 bios bios 618554 2011-03-02 14:37 byte_of_python_v192.pdf</li>
	<li>rw-r--r-- 1 bios bios 1336 2011-05-25 18:03 cluster maps</li>
	<li>rw-r--r-- 1 bios bios 12447 2011-05-25 14:40 clustr_map.jpg</li>
	<li>rw-r--r-- 1 bios bios 338 2011-05-17 19:56 google</li>
	<li>rw-r--r-- 1 bios bios 22647 2011-05-18 17:58 google.odt</li>
	<li>r-------- 1 bios bios 10631201 2011-05-23 17:52 Linux Complete Command Reference.pdf</li>
</ul>
<pre>
drwxr-xr-x 2 bios bios       4096 2011-05-22 18:38 MIT OCW
drwxrwxr-x 4 bios bios       4096 2011-05-22 18:11 moderncv
drwxr-xr-x 2 bios bios       4096 2011-05-22 15:53 progs
drwxr-xr-x 3 bios bios       4096 2011-03-02 14:40 python.org & mercurial tutorials
drwxr-xr-x 2 bios bios       4096 2011-03-02 14:40 python programming pdfs</pre>
<ul>
	<li>rw-r--r-- 1 bios bios 357947 2011-05-25 17:41 rawr.jpg</li>
	<li>rw-r--r-- 1 bios bios 165507 2011-05-23 18:09 Resume.pdf</li>
	<li>rw------- 1 root root 6838939648 2011-04-08 14:40 Win XP.vdi</li>
</ul>
<pre>
Command: pwd
What it does: tells you the current diroctory

pwd stands for Present Working Directory

Example

bios@bios-11:~/vishnu$ pwd
/home/bios/vishnu
Command: cd
What it does: change current directory

Example

bios@bios-11:~$ pwd
/home/bios
bios@bios-11:~$ cd ./vishnu/
bios@bios-11:~/vishnu$ pwd
/home/bios/vishnu

. represents the current directory
.. represents the previous directory

Example

bios@bios-11:~/vishnu$ pwd
/home/bios/vishnu
bios@bios-11:~/vishnu$ cd ./..
bios@bios-11:~$ pwd
/home/bios

From now on all new commands will be separate posts but they’ll come under the Linux commands category.