| Commands | Description |
|---|---|
| ls | To list down all the contents of directory |
| cd | To change the directory |
| cd /bin/ | Change current directory to bin directory |
| cd ~ | The tilde (~) sign signifies the user’s home dir – change dir to home directory |
| cd .. | It changes directory one level up |
| mkdir | To create a directory |
| pwd | It display current directory path |
| cat <filename> | Command to print all the contents of provided filename on the screen |
| cp | It copies the file or directory |
| cp /home/dw /home/linux | It copies the /home/dw/ directory to /home/linux/ directory |
| mv | mv move command is used to move files and directories |
| mv /home/dw/info.txt /newDirectoryName/ | It moves the file info.txt to the /newDirectoryName/ directory. You can also use this command to move the entire directory to another Directory |
| rm | rm command is used to remove files and directories. |
| rm info.txt | This command will remove the file info.txt |
| find | find command perform search of file |
| find / -name “linux*” | The find command is a powerful tool that you can use when searching using the command line. The command here will search for any file or directory with a name that starts with linux |
| uname -a | This command displays information about the machine, the processor architecture, and the operating system details. |
| lscpu | This command returns more information about the system such as the number of CPUs and the CPU speed |
| cat /proc/cpuinfo | This is a file that contains more information than the one displayed using the lscpu command |
| df -h | This command displays the disk space usage in all of the mounted devices. The -h option presents the results in a human readable output, using G for gigabytes or M for megabytes sizes |
| du ~/Downloads | This command displays all the files inside the specified directory and their corresponding file sizes. You can also specify a filename |
| du ~/Downloads -sh | The –s option provides the total file size of the specified directory and -h makes it human readable form |
| Keys | Description | Example |
|---|---|---|
| info | Shows online information about a command | $ info uname |
| man | Shows details (manual) of a command | $ man uname |
| whatis | Shows a short description of a specific keyword | $ whatis uname |
| type | Shows the location of a command file | $ type uname |
| alias | Assign a command alias – especially useful for long commands | $ alias t=type $ t uname $ alias |
| unalias | Remove command alias | $ unalias t |
| pwd | Displays the current directory | $ pwd |
| ln | Create links to files and directories | $ ln -s [file] [soft-link-to-file] $ ln -s info.txt newinfo.txt |
| touch | To trigger a file stamp update for a file | $ touch info.txt |
| find | Search for a file based on the name | $ find [dir-path] -name [filename] $ find . -name info.jpeg |
| whereis | Search for executable files | $ whereis uname |
| which | Search for files in the directories part of the PATH variable | $ which uname |
| dd | Copy lines of data | $ dd conv=ucase Type Hello world ctrl+d $ echo “hello world > info.txt $ dd if=info.txt of=newinfo.txt conv=ucase $ cat newinfo.txt |
| diff | Display the results of comparing two files | $ echo “hello world > info.txt $ echo “hello world > info1.txt $ diff info.txt info1.txt -s $ echo “hello world123 > newinfo.txt $ diff info.txt newinfo.txt -s |
| more | Show a text file one page at a time – display can only go forward | $ ls -R > info.txt $ more info.txt $ ls -R | more |
| less | Show a text file one page at a time – display can only go forward and backwards | $ less info.txt $ ls -R | less |
| wc | Display the count of the number of characters, words, and lines in a file | $ wc info.txt |
| cut | Get sections of text in a file | $ cut -b 1 info.txt $ cut -b 1-3 info.txt $ cut -b 1,3 info.txt |
| grep | Display results of finding expressions in a file | $ cat info.txt | grep Desktop $ cat info.txt | grep -i desktop $ grep -i “desktop” info.txt |
| sed | Perform editing commands, then copy to a standard output | First occurance in every line will be changed $ dw’s/Desktop/Dashboard/’ info.txt 2nd occurance in every line will be changed $ dw ‘s/Desktop/Dashboard/2’ info.txt All occurances will be changed $ dw ‘s/Desktop/Dashboard/g’ info.txt |
| split | Specify a size to break a file into | $ split info.txt $ ls $ rm x* -l100 is 100 lines per file $ split -l100 info.txt $ ls |
| sort | Arrange the lines in a file | $ sort info.txt |
| uniq | Keep unique lines in a file and delete duplicates | $ echo “Hey Hi Hello Commands Linux Irc” > info.txt $ cat info.txt $ uniq info.txt $ uniq info.txt -c $ uniq info.txt -d |
| tar | Archive files with one or more directories | Archive the file $ tar -cf archive.tar file1 file2 Extract the files $ tar -xf archive.tar |
| cal | Show the calendar for the specified month or year | $ cal $ cal -3 $ cal -m 5 $ cal -y 2020 |
| date | Show/Set the current date and time | $ date Sets the system date and time to given date $ date -s “11/20/2003 12:48:00” |
| bg | Run a program or a process in the background | $ bg %[PID] |
| free | Check for the free memory | $free |
| kill | Stop a process | $ kill <PSID> |
| nice | Run a program with a low priority, niceness values range from -20 to 19, with the former being most favorable, while latter being least | $ nice -10 ls -R $ nice –10 ls -R |
| ps | Show current running processes | $ps |
| top | Show list of CPU and memory utilization of processes |
$top |
| reboot | Restart the system | $reboot |
| shutdown | Turn off system | $shutdown |
