https://github.com/deroyace/linux-cmds
Basic Linux terminal commands for beginners
https://github.com/deroyace/linux-cmds
cheatsheet cli command-line linux linux-command linux-command-line linux-commands-cheatsheet unix unix-command
Last synced: 13 days ago
JSON representation
Basic Linux terminal commands for beginners
- Host: GitHub
- URL: https://github.com/deroyace/linux-cmds
- Owner: DeRoyace
- Created: 2022-02-15T14:58:01.000Z (over 3 years ago)
- Default Branch: master
- Last Pushed: 2024-06-21T19:00:17.000Z (11 months ago)
- Last Synced: 2025-05-07T05:09:57.504Z (13 days ago)
- Topics: cheatsheet, cli, command-line, linux, linux-command, linux-command-line, linux-commands-cheatsheet, unix, unix-command
- Homepage:
- Size: 965 KB
- Stars: 5
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
# Linux Commands
## ls command
- `ls` : to list directories and files
- `ls -a` : to list all files and directories alongwith hidden ones
- `ls -r` : lists files and directories in reverse alphabetical order.
- `ls -l ` : to give detailed info of directories/files like when created and by whom, date modified, size, permissions and ownerships
- `ls -al` : to list all hidden files with details.
- `ls -lh` : to list file with details of file size in - KB (kilobytes).
- `ls -lR` : to list all the directories and their - sub-directories with details.
- `ls -lR dirName` : to list the details of - sub-directories of the specified dirName.
- `ls -F` : to identify files and directories - seperately. Directories will be listed with a "/" - symbol at the end of directory name
- `ls -i` : displays the inode [index number] of each - file
- `ls --sort=t` or `ls -t` : displays the list of files / directory sorted by time. Similarly sort=v/s/e for sort by version/size/extension
## Directory
### Directory Creation
- `mkdir [FOLDER-NAME]` : to create a folder/ directory
- `mkdir folder1 folder2 folder3` : to create multiple folders/ directory at once
- `mkdir file{1..9}` : this will create 10 folders with name 'file 1', 'file 2', ..., 'file 10'
- `mkdir -v folders{1..7}` : this will create folders & will skip the ones which are already created before with the same name.
- `mkdir -p [PATH]` : will create 'cmds' folder in the given path but if the path doesn't exits then it will be created.
### Remove directoy
- `rmdir [DIR-NAME]` : to remove the file/ folder/ directory.
- `rmdir myFolder*` : removes all folders that begins with name 'myFolder'
- `rmdir *` : removes all the folder in the present directory.
- `rmdir myFolder{1..7}` : removes the folders from 'myFolder 1' to 'myFolder 7'
NOTE: rmdir cannot delete diectories having files / folders inside.
- `rm -R [DIR-NAME]` : to delete the directory with the files inside.
- `rm -r [DIR-NAME]`: to delete all the files and NON-EMPTY directories and also the child folders content.
### Change Directory
- `cd` : to change directory to home/user directory
- `cd ~` : to go to home/user directory
- `cd /` : to go to root directory
- `cd [DIR-NAME]` : to change directory or go to that directory
- `cd ..` : to go to the parent directory
## File management
### Create or manipulate file
- `touch [FILE-NAME]` : to create a file
- `touch -m [FILE-NAME]` : change modification time of the file
- `touch -a [FILE-NAME]` : change the access time of the file
- `touch test{1..5}.txt` : create 5 files with name test1.txt, test2.txt, ..., test5.txt
- `cat > [FILE-NAME]` : to rewrite a file. If the filename not present then new file with given name will be created
- `cat >> [FILE-NAME]` : to append new contents to the file
[ **NOTE**: _for cat > or >> ... commands, inorder to exit writing mode of the file press CTRL+D._]
### Delete files
- `rm [FILE-NAME]` : to remove dir/ file/ folder.
- `rm *` : removes all the files in the current directory.
- `rm *.txt` : removes all the files in the current directory that has .txt extension.
- `rm -i [FILENAME]` : to make command prompt the user with each filename while deleting
### Move and Copy
- `mv [SOURCE] [DESTINATION]` : to move the file into the given destination or path.
- `cp [FILE-1] [FILE-2]` : copies the file1 contents to file2.
- `cp [FILE-NAME]` : will copy the file in the directory.
### Show file contents
- `cat [FILE-NAME]` : to show the contents of file in the terminals.
### Change filename
- `mk [PRESENT-FILENAME] [NEW-FILENAME]` : this changes the file or folder name.
### Octal form
- `od [FILENAME]` : to display a file contents in octal form
### file command
- used to display file type
```
file video.mp4
```
Output:
```
video.mp4: ISO Media, MP4 Base Media v1 [ISO 14496-12:2003]
```
### Locate a file
- `find [FILENAME]` : search for files in a directory hierarchy
### File Comparison
#### cmp command
- Compare two files byte by byte
```
cmp file1.txt file2.txt
```
Output:
```
file1.txt file2.txt differ: byte 8, line 1
```
#### diff command
- used to compare files line by line
```
diff [FILE-1] [FILE-2]
```
Examples:
- to show the difference of two files side by side
```
diff -y file1.txt file2.txt
```
- `-y` : side-by-side output in two columns
#### comm command
- Used to compare two sorted files
Contents of file1.txt :
```
ANGULAR
DJANGO
ELECTRON
FLASK
NODEJS
REACT
YARN
```
Contents of file2.txt :
```
ANGULAR JS
FASTAPI
FLASK
NEXT JS
NODEJS
REACTJS
YARN
```
Command line input:
```
comm --total file1.txt file2.txt
```
Output:
```
ANGULAR
ANGULAR JS
DJANGO
ELECTRON
FASTAPI
FLASK
NEXT JS
NODEJS
REACT
REACTJS
YARN
4 4 3 total
```
- unmatched file of first file is displayed in 1st column
- unmatched file of first file is displayed in 2nd column
- matched lines in 3rd column
- `--total` : counts the number of lines that are matched and unmatched for both the files.
### File Permissions
#### chmod (change mode)
- use to change permissions of a file or directory of all types of users
- Control of a file:
- `d` : directrory
- `-` : no permission given [NOTE: the leftmost `-` implies its a file]
- Permissions
- `r` : read(4)
- `w` : write (2)
- `x` : executable (1)
Example:
```
chmod +x program.sh
```
The above command grants executable permissions to the program.sh file for all the users
```
-rwxrwxr-x 1 deroyace deroyace 127 May 23 15:3 counter.sh
drwxr-xr-x 3 deroyace deroyace 4096 Mar 29 19:2 Desktop
```
- `rwx` is written 3 times consecutively. This means,
- first set of rwx implies **USER / OWNER** permission
- second set implies **GROUP** permissions same as owner.
- third set implies **OTHERs** outside the group.
- left most single symbol `d` indicates it is a directory. It can be `l` or `-` also.
- `l` means its a shortcut link of a file or a directory.
- `-` means it is a file.
- **Numerical Short hand or Octal Mode**
- Another way to use chmod is to provide the permissions you wish to give to the owner, group, and others as a three-digit number which is basically octets that are formed by combinations of 4,2 and 1.
- The leftmost digit represents the permissions for the owner.
- The middle digit represents the permissions for the group members.
- The rightmost digit represents the permissions for the others.
Value Symbols Meanings/ Permissons
0 --- No permission
1 --x Execute
2 -w- Write
3 -wx Write and execute
4 r-- Read
5 r-x Read and execute
6 rw- Read and write
7 rwx Read, write, and execute
Examples:
- Give read, write, execution permissions to all types of users:
```
chmod 777 program.sh
```
- Give read, write, execution permissions only to User and Group:
```
chmod 770 program.sh
```
- Give read, write, execution permissions to User and read nad execution permission to Group and only execution permission to other users:
```
chmod 751 program.sh
```
- Default permissions for:
- `file` : **664** (-rw-rw-r--)
- `folder` : **775** (drwxrwxr-x)
- **Symbolic Mode**
```
Symbol Meaning
-------------------
a all users
u user
g group
o others
```
Examples:
- Give read, write, execute permission to user and execute permission to group and other
```
chmod u+rwx,go+x program.sh
```
- Give read permission to all, write permission to user and group, execute persmission to group only:
```
chmod u+rw,g+rx,o+r program.sh
```
- Give read, write, execute permission to user and execute permission to group and other:
```
chmod u+rwx,go+x program.sh
```
- Make all files and sub-directories in the directory TEST executable by all users
```
chmod -R a+x TEST
```
- Remove executable permission from group and other of a file
```
chmod go-x file.txt
```
#### chgrp (change group)
- `chgrp [GROUP-NAME] [FILE/FOLDER NAME]`
: to assign a file/folder to a specific group
#### chown (change owner)
- `sudo chown [USER-NAME] [FILE/FOLDER-NAME]`
: to change the user or ownership of a file/folder:
### File Compression
#### tar command
- it is used to compress and archive files
- **TAR** short for Tape Archive
Examples:
- To create a tar and includes the files specified in the command:
```
tar cf file.tar [FILE-NAMES]
```
- `c` : create new archive
- `f` : to specify name of the archive files
- `[FILE-NAMES]` : represent files that are to be included in the tar file
- Extract From tar Archive
```
tar xf file.tar
```
- `x` : extract files from an archive
- Creating an uncompressed tar Archive:
```
tar cvf file.tar *.sh
```
- This command creates a **tar** file called `file.tar` which is the **Archive** of all `.sh` files in the current directory.
- `v` : verbosely list files processed
- Extracting from uncompressed tar archive:
```
tar xvf file.tar
```
- Create a tar.gz Compressed Archive:
```
tar czf files.tar.gz files
```
- Extract files from tar.gz
```
tar xzf files.tar.gz
```
## Wild cards
- `*`, `?` are wilcards
- Use of wild cards:
- `ls *.txt` : list all files that ends with .txt extension
- `*` implies any number of characters
- To list all files that starts with "file" and succeeds by any one character and then ".txt":
`ls file?.txt`
- `ls file???.txt`
- `?` two characters
- `???` means any 3 character
## sort command
- to sort lines of text files lexicographically
Examples:
- sort the lines of file in alphabetical order:
```
sort [FILENAME]
```
- sort the lines of file in reverse order:
```
sort -r [FILENAME]
```
- output the sorted file into a new file:
```
sort [FILENAME] > [NEW-FILE]
```
- output the sorted lines of a file into a new file without duplicates:
```
sort [FILENAME] > uniq > [NEW-FILE]
```
## ln command
- used to make links between files
- `ln [FILE-NAME] [HARD-LINK]`: Create a hard link for a file (same inode)
- `ln -s [FILE-NAME] [SOFT-LINK]`: Create a soft link for a file
- `ln -s .. [SOFT-LINK]`: Create a soft link for the parent directory you are currently located in
## grep command
- prints each line of a file that matches a pattern
Examples:
- list all directories present in the current folder
```
ls -l | grep ^d
```
- `^d` : matches those lines that starts with letter 'd'
Output:
- Show the line numbers that matches the pattern "hello", ignoring case
```
grep -i -n "hello" file.txt
```
- `-n` : displays line number
- `-i` : ignores case
- Ignore those lines that matches the pattern "hello"
```
grep -v "hello" [FILENAME]
```
- To highlight words in a file or command output that ends with letter 'A':
```
grep "\b\w*A\b" [FILENAME]
```
- `-b` : boundary
- `\w*` : any number of characters
- Specifically display and highlight only those words that starts with letter 'A' or 'a':
```
grep -o -i "\b\A\w*\b" [FILENAME]
```
- `-o` : outputs only matching words
- `-i` : ignores case [ _NOTE: it works only when capital letter is used in the command to find the required search. ]_
## CUT
- used to extract characters or remove sections from each lines of files
Examples:
- To extract first three characters of every line:
```
cut -c -3 [FILENAME]
```
- To extract characters starting from 2nd character of every line:
```
cut -c 2- [FILENAME]
```
- To extract last three characters of every line:
```
cat [FILENAME] | rev | cut -c -3 | rev
```
- To display selected columns sorted by ID:
```
cut -d $'\t' -f1-4 movies.txt | sort -k1 -n
```
- `$'\t'` : tab space delimiter [taking columns seperated by TAB space]
- `-d` : delimiter
- `-n` : numeric value sorted
- `-f1-4` : columns 1 to 4
- `-k1` : sort by first column
- `-k2` : sort by second column
## PASTE
- `paste [FILENAME-1] [FILENAME-2]` : concatenates two files. by default the delimiter is TAB
- To explicity specify a delimiter/ concat file contents using delimiter:
```
paste -d '-' [FILENAME-1] [FILENAME-2]
```
## User and Group handling
### Switch user
- `su root` : to go to the root account. '$' will change to '#'; su -> switch user
- `sudo su` : switching user
### User Password
- `passwd` : to change your login or root account password.
- `passwd [Account Name]` : to change password of that particular account.
- `id [USER-NAME]` : shows user id; root account id is 0.
### Create New User / Group
- `sudo adddgroup [GROUP-NAME]`
: to create new User Group
- `sudo adduser [USERNAME]` : to create a new user account.
- `sudo usermod -aG sudo [USERNAME]` : to make the user as a root user.
### Remove User / Group
- `sudo groupdel {GROUP-NAME}`
: to remove a group:
## Process management
- `top`: list all processes and shows the cpu, memory usage and running background apps.
- `ps aux` : lists all processes that are currently running in the device.
- `a` : --all Display information about other users' processes as well as your own.
- `u` : Display the processes belonging to the specified usernames.
- `x` : When displaying processes matched by other options, include processes which do not have a controlling terminal.
- `kill [PID]` : kills or disables a process
- `kill -9 [PID]` : stop a process
## OS, CPU and Kernel information
- `uname -a` : show kernel information
- `xdpyinfo | grep 'dimensions:'` : to check screen resolution
Result from above cmd: dimensions: 1366x768 pixels (361x203 millimeters)
- To check distro release version:
- `lsb_release -a` : provides certain LSB (Linux Standard Base) and distribution-specific information.
- `cat /etc/os-release`
- `echo $XDG_CURRENT_DESKTOP` : to check Desktop Environment
- `cat /proc/cpuinfo` : cpu information
## Memory information
- `df` : shows the disk space usage
- `du` : shows directory space usage
- `free` : shows memory and swap usage
- `cat /proc/meminfo` : memory information
## Path Locate
- `pwd` : shows the path of current working directory
- `locate [SEARCH-NAME]` : to search files by name
- `whereis [APP/COMMAND]` : to locate binary file, manual page files of applications or commands
- `which [APP/COMMAND]`: to locate a command or an application
## Other useful commands
- `man [COMMAND]` : shows the mannual page of the command
- `history` : list all the cmds used (last 500 cmds)
- `lsusb` : shows the USB buses and devices connected
- `whatis [COMMAND]` : to give brief description or use of that command
- `whoami` : checks whether you are root user/ whats the user name you are logged in as
- `who` : display information about users who are currently logged in
- `w` : show who is logged on and what they are doing
- `tty` : print the file name of the terminal connected to standard input
- `!!` : executes the last command
- `exit` : log out current session
## Shortcuts
- `CTRL + ALT + T` : to open terminal [_NOTE: this may vary in distros, may not work for some_]
- `CTRL + SHIFT + W`
or
`CTRL + D` : to close terminal
- `CTRL + L` : to clear the terminal
- `CTRL + C` : to terminate the program
- `CTRL + D` : TO log out of current session, similar to exit
- `CTRL + Z` : to pause/suspend the program
- `CTRL + A` : to go to start of the line/ command
- `CTRL + E` : to go to end of the line/ command
- `CTRL + U` : to clear the command
- `CTRL + R` : type to bring up a recent command
---