Linux Basic Commands with Examples
Before learning the Linux basic commands, its suggested to have some basic understanding of Linux -
- Linux is not O.S, it is actually a Kernel
- Flavour of Linux are RedHat, Fedora, OpenSue etc
- Linux kernel is free to use and modify
- Latest version of Linux kernel is 5.x
There are various commands used in Linux, but here is a list of commonly used -
Commands for File operations
1. ls - Directory listing
2. ls -al - Formatted listing with hidden files
3. ls -lt - Sorting the Formatted listing by time modification
4. cd dir - Change directory to dir
5. cd - Change to home directory
6. pwd - Show current working directory
7. mkdir - dir Creating a directory dir
8. cat >file - Places the standard input into the file
9. more file - Output the contents of the file
10. head file - Output the first 10 lines of the file
11. tail file - Output the last 10 lines of the file
12. tail -f file - Output the contents of file as it grows,starting with the last 10 lines
13. touch file - Create or update file
14. rm file - Deleting the file
15. rm -r dir - Deleting the directory
16. rm -f file - Force to remove the file
17. rm -rf dir - Force to remove the directory dir
18. cp file1 file2 - Copy the contents of file1 to file2
19. cp -r dir1 dir2 - Copy dir1 to dir2;create dir2 if not present
20. mv file1 file2 - Rename or move file1 to file2,if file2 is an existing directory
21. ln -s file - link Create symbolic link link to file
Commands for Process management
1. ps - To display the currently working processes
2. top - Display all running process
3. kill pid - Kill the process with given pid
4. killall proc - Kill all the process named proc
5. pkill pattern - Will kill all processes matching the pattern
6. bg - List stopped or background jobs,resume a stopped
job in the background
7. fg - Brings the most recent job to foreground
8. fg n - Brings job n to the foreground
1. chmod octal file - Change the permission of file to octal
1. grep pattern file - Search for pattern in file
2. grep -r pattern dir - Search recursively for pattern in dir 3. command | grep
pattern
Search pattern in the output of a command
4. locate file - Find all instances of file
5. find . -name - filename Searches in the current directory (represented by
a period) and below it, for files and directories with
names starting with filename
6. pgrep pattern - Searches for all the named processesCommands for File permission
which can be found separately for user,group,world by adding -
Commands for Searching
that
matches with the pattern and, by default, returns
their ID
Commands for System Info
1. date - Show the current date and time
2. cal - Show this month's calender
3. uptime -0 Show current uptime
4. w - Display who is on line
5. whoami - Who you are logged in as
6. finger user Display information about user
7. uname -a Show kernel information
8. cat /proc/cpuinfo Cpu information
9. cat proc/meminfo - Memory information
10. man command - Show the manual for command
11. df - Show the disk usage
12. du - Show directory space usage
13. free - Show memory and swap usage
14. whereis app - Show possible locations of app
15. which app - Show which applications will be run by default
Commands for Compression
1. tar cf file.tar file - Create tar named file.tar containing file
2. tar xf file.tar - Extract the files from file.tar
3. tar czf file.tar.gz files - Create a tar with Gzip compression
4. tar xzf file.tar.gz - Extract a tar using Gzip
5. tar cjf file.tar.bz2 - Create tar with Bzip2 compression
6. tar xjf file.tar.bz2 - Extract a tar using Bzip2
7. gzip file - Compresses file and renames it to file.gz
8. gzip -d file.gz - Decompresses file.gz back to file
Commands for Networking
1. ping host - Ping host and output results
2. whois domain - Get whois information for domains
3. dig domain - Get DNS information for domain
4. dig -x host - Reverse lookup host
5. wget file - Download file
6. wget -c file - Continue a stopped download
Shortcuts Commands used in Linux
1. ctrl+c - Halts the current command
2. ctrl+z - Stops the current command, resume with fg in the foreground or bg in the background
3. ctrl+d - Logout the current session, similar to exit
4. ctrl+w - Erases one word in the current line
5. ctrl+u - Erases the whole line
6. ctrl+r - Type to bring up a recent command
7. !! - Repeats the last command
8. exit - Logout the current session