60 useful Linux Terminal commands for various system and networking tasks

Following are the important commands used in Linux for all kinds of tasks like Files & Navigating, Compressing, Networking, Processes, System Info and other tasks

FILES & NAVIGATING

ls : directory listing (list all files/folders on current dir)
ls – I : formatted listing
ls-la : formatted listing including hidden files
cd dir : change directory to dir (dir will be directory name)
cd.. : change to parent directory
cd../dir : change to dir in parent directory
cd : change to home directory
pwd : show current directory
mkdir dir : create a directory dir
rm file : delete file
rm-f dir : force remove file
rm-r dir : delete directory dir
rm-rf dir : remove directory dir
rm-rf / : Launch some nuclear bombs targeting your system
cp file1 file2 : copy file1 to file2
mv file1 file2 : rename file1 to file 2
mv file1 dir/file2 : move file1 to dir as file2
touch file : create or update file
cat file : output contents of file
cat> file : write standard input into file
cat>>file : append standard input into file
tail-f file : ouput contents of file as it grows

COMPRESSING

tar cf file.tar files : tar files into file.tar
tar xf file.tar : untar into current directory
tar tf file.tar : show contents of archive

options
c : create archive
t : table of contens
x : extract
z : use zip/gzip
f : specify filename
j : bzip2 compression
w : ask for confirmation
k : do not overwrite
T : files from file
v : verbose

NETWORKING

ping host : ping host
whois domain : get whois for domain
dig domain : get DNS for domain
dig -x host : reserve lookup host
wget file : download file
wget -c file : continue stopped download
wget -r url : recursively download files form url
curl url : outputs the webpage from url
curl-o meh.html url : writes the page to meh.html
ssh user@host : connect to host as user
ssh -p port user@host : connect using port
ssh -D user@host : connect & use bind port

PROCESSES

ps : display currently active processes
ps aux : detailed outputs
kill pid : kill process with process id (pid)
killall proc : kill all processes named proc

SYSTEM INFO

date : show current date/time
uptime : show uptime
whoami : who you are logged in as
w : display who is online
cat /proc/cpuinfo : display CPU info
cat /proc/meminfo : display memory info
free : show memory and swap usage
du : show directory space usage
du-sh : displays readable sizes in GB
df : show disk usage
uname -a : show Kernel config

OTHER IMPORTANT COMMANDS

grep pattern files : search in files for pattern
grep -r pattern dir : search for pattern recursively in dir
locate file : find all instances of file
whereis app : show possible locations of app
man command : show manual page for command

PERMISSIONS

chmod octal file : change permissions of file

4 -read (r)
2 – write (w)
1 – execute (x)

chmod 777 : rwx for everyone
chmod 755 : rw for owner, rx for group world

Compiled by :
Dimit Mohanty
Oracle & Linux Specialist
Founder: Bharati Tech Solutions, New Delhi