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Bash - Bourne again shell

Bash is the default shell of most Linux distros.

  • Ctrl + a -- Go to the beginning of the line
  • Ctrl + e -- Go to the end of the line
  • Alt + f -- Move cursor to the next word
  • Alt + b -- Move cursor to the previous word
  • Ctrl + x, x -- Move cursor between the current position and the begining of the line

Editing​

  • Ctrl + k -- Cut line after cursor and copy it to the clipboard
  • Ctrl + u -- Cut line before cursor and copy it to the clipboard
  • Ctrl + y -- Paste what you have on the clipbaord
  • Ctrl + _ -- Undo your last key press

Processing​

  • Ctrl + c -- Kill the currently running command
  • Ctrl + d -- Exit the shell
  • Ctrl + l -- Clear the screen (Same as the clear command)

History​

  • Alt + p -- Search backward through the history starting at the current line
  • Alt + n -- Search forward through the history starting at the current line
  • Ctrl + r -- Open the history search

Tips​

Install Bash-completion​

Bash-completion helps you type commands faster and easiler.

# Ubuntu
sudo apt install bash-completion

# Rocky
sudo dnf install bash-completion

Press [TAB] when you type commands, for example:

sudo git [TAB]
sudo systemctl [TAB]

History search with arrow keys​

You can enable arrow keys -- [Up] for backward and [Down] for forward -- for history search by these commands (You can put them in your .bashrc.)

bind '"\e[A": history-search-backward'
bind '"\e[B": history-search-forward'

Write a file in a script​

Create a new file / Overwrite an existing file

tee /tmp/test.txt <<EOF
This is the 1st line
This is the 2nd line
EOF

Append new lines

tee -a /tmp/test.txt <<EOF
This is the 3rd line
This is the 4th line
EOF

Array in Bash script​

test_array.sh
myArray=("cat" "dog" "mouse" "frog")

echo ${myArray[@]}
echo ${!myArray[@]}

for str in ${myArray[@]}; do
  echo $str
done

for i in ${!myArray[@]}; do
  echo "element $i is ${myArray[$i]}"
done