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The most important to be known for using LINUX is the commands. Below is some of the Basic Linux Commands.

* - Be Careful while using this Command

File Commands

ls — for directory listing

ls -al — Formatted Listing with hidden files

cd <dir> — Change directory to <dir>

cd — Change to home directory

pwd — shows the current working directory

mkdir <dir> — create a directory <dir>

rm <file> — Delete <file>

rm -r <dir> — delete directory <dir>

rm -f <file> — force remove <file>

rm -rf <dir> — force remove directory <dir> *

cp <file1> <file2> — copy <file1> to <file2>

cp -r <dir1> <dir2> — Copy <dir1> to <dir2>, creates dir2 if it doesn’t exist.

mv <file1> <file2> — Rename or Move <file1> <file2>, if file2 is an existing directory, moves <file1> into directory <file2>

ln -s <file1> <link> — Create symbolic <link> to <file1>

touch <file> — Create an empty file.

cat > <file> — Pleaces standard input into file

more <file> — Output the contents of file

read <file> — Output the first 10 lines of file

tail <file> — Output the last 10 lines of file

tail -f <file> — Output the contents of file as it grows, starting with the last 10 lines

Process Management
ps — Display your currently active processestop — Display all running processeskill <pid> — Kill process id pidkillall <proc> — Kill all processes named <proc> *bg — Lists stopped or background jobs; resume a stopped job in the background

fg — Brings the most recent job to foreground

fg n — Brings job n to the foreground

File Permissions chmod octal file — Change the permissions of file to octal, which can be found separately for user, group, and world by adding:

• read (r)
• write (w)
• execute (x)

Examples:

chmod 777 <file> — read, write, execute for all of a <file>

chmod 755 <file> — rwx for owner, rx for group and world of a <file>

chmod -R 755 <dir> — rwx for owner, rx for group and world of a <dir>

For more options, see man chmod.

SSH

ssh user@host — Connect to host as user

ssh -p port user@host — Connect to host on port

port as user

ssh-copy-id user@host — Add your key to host for user to enable a keyed or passwordless login

Example:

ssh guest@172.168.60.25 — if the Hostname of the remote machine is not known/Entry not in the Hosts List(/etc/hosts).

ssh guest@<remote_hostname>– If the Hostname of the remote machine is known.

Searching

grep pattern files — Search for pattern in files

grep -r pattern dir — Search recursively for pattern in dir

command | grep pattern — Search for pattern in the output of command

locate file — Find all instances of file.

System Info

date — Show the current date and time

cal — Show this month’s calendar

uptime — Show current uptime

w — Display who is online

whoami — Who you are logged in as

finger user — Display information about user

uname -a — Show kernel information

cat /proc/cpuinfo — CPU information

cat /proc/meminfo — Memory information

man <command> — Show the manual for command

df — Show disk usage

du — Show directory space usage

free — Show memory and swap usage

whereis <app_name> — Show possible locations of app (ex: whereis ls)

which <app_name> — Show which app will be run by default

Compression

tar -cvf <file.tar> <files> – create a tar named <file.tar> containing <files>

tar -xvf <file.tar> — Extract the files from <file.tar>

tar -cvzf <file.tar.gz> <files> — Create a tar with Gzip compression

tar -xvzf <file.tar.gz> — Extract a tar using Gzip

tar -cvjf <file.tar.bz2> — Create a tar with Bzip2 compression

tar -xvjf <file.tar.bz2> — Extract a tar using Bzip2

gzip <file> — Compresses file and renames it to <file.gz>

gzip -d <file.gz> — Decompresses <file.gz> back to <file>

Network

ping <host/IP> — Ping host/IP and output results

whois domain — Get whois information for domain

dig domain — Get DNS information for domain

dig -x host — Reverse lookup host

wget <file> — Download file

wget -c <file> — Continue a stopped download

Installation

Install from source:

./configure

make

make install

dpkg -i pkg.deb – install a package (Debian)

rpm -Uvh pkg.rpm – install a package (RPM)

For Detailed: http://blog.linuxgalore.com/2007/11/27/how-to-install-a-software-in-linux-from-source/

Shortcuts

Ctrl+C — Halts the current command

Ctrl+Z — Stops the current command, resume with fg in the foreground or bg in the background

Ctrl+D — Log out of current session, similar to exit

Ctrl+W — Erases one word in the current line

Ctrl+U — Erases the whole line

Ctrl+R — Type to bring up a recent command

!! — Repeats the last command

exit — Log out of current session

Keep checking for more updates on this…………… and leave your comments.

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