Linux Commands
Are you looking for Linux Cheat Sheet? Or most used linux commands? I am putting up a list below for my own reference that could come in handy to you as and when you need it. I hope you like it!
System Info
date – Display current date and time
- cal – show current month’s calender
- uptime – show current server’s uptime since last reboot
- w – display which user’s are logged in and average load on the server
- whoami – who you are logged in as (funny!)
- finder username – Get information about A specific user on the system
- uname – a – Display kernal information
- cat /proc/cpuinfo – Display CPU information
- cat /proc/meminfo – Display Memory (RAM) info
- man command – Show Manual for any “command”
- df – show disk usage
- du – show directory space usage
- df -h – show all HDD’s and their mount point
- free – show RAM and its swap usage (free -m to display in MB)
- whereis app – Find location of an app
Network
- ping – ping any IP / Host and output result
- whois domain.tld – Get whois information of any domain name
- dig domain.tld – Get DNS information of any domain
- dig -x host – Reverse lookup
- wget file-location – Download any remote file
- wget -c file – Continue a paused / stopped download
File Commands
- ls – List directories
- ls -al – Formatted listing with hidden files
- cd dir – Change to DIR
- cd – Switch to home
- pwd – Show current directory
- mkdir name – Create a new directory called “name”
- rm filename – Delete a file
- rm -r dir – Delete an EMPTY directory called “dir”
- rm -rf dir – Delete an entire directory with files called “dir”
- cp file1 file2 – Copy file1 to file2
- mv file1 file2 – Move or Rename a file
- touch file – Create or Update a file
- more file – Output the content of the file
- tail file – Output last 10 lines of a file
Compression
- tar cf file.tar files – Create a tarball compressing the folder called “files”
- tar xf file.tar – Exact the tarball “file.tar”
- gzip filename - Compress and rename the file to filename.gz
File Permissions
- 4 – Read (r)
- 2- Write (w)
- 1- Execute (x)
- Example : “chmod 777 filename” will allocation read, write & execute permission to filename.
Searching
- grep pattern files – search for a pattern in files
- grep -r pattern dir – Search recursively for pattern in dir
- command | grep pattern – Search for pattern in output command
- locate file – Find all instances of file
Process Management
- ps – Display all current active processes
- top – Display all running processes
- top -c – Display processes using top CPU
- top -m – Display processes using top Memory (RAM)
- kill pid – Kill a process with its pid
- bg – List stopped background jobs
- fg – Bring the most recent job to the foreground
SSH
- ssh user@hostname – connect to a host as a user
- ssh -p 22 user@host – Connect to a host as a user on specific port (in this case 22)
- ssh-copy-id user@host – Add your key to host for user to enable a keyed or password-less login
Shortcuts
- Ctrl + C – Halts the current command
- Ctril + Z – Stops the current command, you can resume it with fg in the foreground and bg in the background
- Ctril + D – Logout of current session
- Ctrl + U – Erase the line
- Ctrl + R – Type to bring up a recent command
- !! – Repeat the last command
- exit – Logout of current session
- abc* – Every file / dir / etc starting with abc
I hope you liked the sheet and will make use of it. In case you think I have forgotten anything, feel free to add it in the command and I will get the main sheet updated.
