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Linux Commands

  • whereis - Find the path of that executable file.

List operation​

  • ls - Shows list.
    • -a - Hidden file.
    • -l - Permission.
    • -R - Show sub dir.

Changing dir operation​

  • cd <folder-name> - Change Dir.
  • cd .. - Go one Directory back.
  • cd - Go to home.
  • cd ../<foldername> - Open a previous dir folder.
  • cd <path> - Open a dir with the path.

File/Folder Ope.​

  • mkdir <new-dir-name> - Create a new folder.
  • mkdir -p test/test1/test2 - Create a dir between two directories.
  • touch <new-file-name> - create a blank file.
  • pwd - Present working directory.
  • cat <filename> - Display file content.
  • cat > <new-file-name> - Create a file.
  • dd if=/dev/zero of=bos_dosya bs=4G count=1- create empty file with zeros
  • cat >> <filename> - Append the file
  • cat <filename1> >> <filename2> - Append the content of the file filename1 at the end of the file <filename2> .
  • cat <filename> <filename2> - Display 2 files at a time.
  • cat <filename> <filename2> > <newfile-name> - Merge both of file content in a single one.
  • cat <file-name> | tr > <new-file-name> - Translate the file.
  • cut -c 1-2 <filename> - cut the file column wise
  • echo "Hello" >> <file-name>
  • man <commad name> - Know about the command usages and options.
  • man <commad name> - know about the command.

File/Folder operation​

  • cp <file-name> <new-fie-name> - Make a copy of a file in the current location.
  • mv <file-name> <dir-path> - Move a file from one dir to another.
  • mv <file-name> <new-fie-name> - Rename a file.
  • mv -R <dir-name> <dir-path> - Move Dir
  • rm <file-name> - Remove a file permanently.
  • rm -R <file-name> - Delete a folder with dir included.
  • head <file-name> - Will display first 10 lines of a file.
  • tail <file-name> - Will display last 10 lines of a file. --n 2 - will display last 2 lines.
  • diff <file-1> <file-2> - Show diff between the two files.
  • locate <file> - To find out the file.
  • find <file/folder-name> - Find a file/folder.
  • find <dir-name> - Find files inside the dir
  • find .-type d - Show only dir.
    • .-type f - show only files.
    • .-type f -name "*.txt" - Show only files with that specific name.
    • .-type f -iname "*.txt" - Show only files with that specific name - not case sensitive (i)
    • .-type f -mmin -20 - Show files which modify less than 20 min ago.
    • .-type f -mmin +20 - show files which modify more than 20 min ago.
    • .-type f -maxdepth 2 - Will only show 1 folder deep.
    • .-size +1k - will only show file/folder with size of 1kb

System commands​

  • ps aux - processes which are running
  • systemctl [option] [service] - interact with a process
    • We can do 4 option with systemctl
      • start
      • stop
      • enable
      • disable
    • Example, systemctl start apache2
  • df - Check the capacity and storage details.
    • m - In megabyte or
    • hg - In gigabyte.
  • du - Disk usages capcity
    • -h (human readable)
  • echo - Get a output of a string
  • echo $PATH - Check the path variable
  • sudo - Admin command
  • sudo chown root text.txt - change owner
  • !<command-name> - Run the previous command
  • git add .; git commit -m "message" - Run multiple commands at a time
  • sort <file-name>" - sort the file
  • job - show the jobs
  • wget <url> - download the file from the URL
  • top - what processes are running
  • kill <process-id> -stop that process
  • Uname - show the system info
  • zip <file-1> <file-2> - Zip Two or more files
  • Unzip <file-name> - Unzip files
  • useradd <name> - add a user
  • passwd <name> - set a password for the user
  • uname -<flag> -o -m -r
  • lscpu - get cpu details
  • free - free memory
  • vmstat - virtual memory
  • lsof - list all the open file
  • xdg-open <file-fath> - open the folder (graphical window) of a file/folder with path.
  • xdg-open . - open the folder of the current directory.
  • vi ~/.bashrc - set your Alias
  • echo -n 'username' | base64 - encode the username to base64
  • echo -n 'encoded' | base64 -d - decode the username to base64

Networking​

  • nslookup google.com - To check the IP address of the domain.
  • netstat - To check the network status.
  • hostname - To check the hostname.
  • whoami - To check the current user.
  • ping google.com - To check the connectivity.

Permissions​

  • chmod u=rwx,g=rxw,o=rwx <file-name> READ, WRITE AND EXECUTE
  • chmod 777 <file-name> - 4- Read, 2- Write, 1 - Execute
  • find . -perm 777 - shows files with all permissions(rwx)
  • grep <keyword> <file-name> - To search if the keyword is presnt in the file or not
  • grep -w <keyword> <file-name> - To search if the keyword is present in the file or not (complete word)
  • grep -i <keyword> <file-name> - To search if the keyword is present in the file or not (not case sens)
  • grep -n <keyword> <file-name> - To search if the keyword is present in the file or not (Line number)
  • grep -B <keyword> <file-name> - Show Line before that keyword
  • grep -win <keyword> ./*.txt - To search if the keyword is present in the file in current dir
  • grep -win -r <keyword> .*
  • history | grep "ls -l" - Piping, we filter out the things
history
!<number-from-history>

Operators

  • ping google.com & ping facebook.com - run both the commands at the same time
  • echo "google.com" && echo "facebook.com" - second will only run if first is successful
  • echo "google.com" && {echo "facebook.com"; eco "pradumnasaraf.co"}
  • echo "google.com" || echo "pingfacebook.com" - second will only run if first is not successful
  • rm -r !(file.txt) - delete all files except file.txt
  • printevnv - to print all th env.