JC’s Favorite BASH Commands
1. Force the system to check all file systems at boot:
sudo touch /forcefsck
2. Use cat to create or append text files;
cat > myfile.txt
— Creates small text file. Use Ctrl+D to send text to file.
cat >> myfile.txt
— Appends lines to bottom of pre-existing file.
3. Use pushd and popd to put move directories on and off of a stack.
pushd /directory
— Moves to new directory.
popd
— brigs you back to original directory
4. Open new root bash environment:
sudo bash
— Use “exit” to return to your onw shell.
5. Make bash execute one command as root:
sudo bash -c “echo ‘QT_QPA_PLATFORMTHEME=gtk2’ >> /etc/environment”
— Note: “sudo echo” at a command prompt will not work.
6. Use wget to download files from the internet:
wget https://dl.google.com/linux/direct/google-chrome-stable_current_amd64.deb
— Downloads Google Chrome installer package into the current directory.
7. Automaticallly look for and install packages in a script:
dpkg -l | grep -qw gdebi || sudo apt-get install -yyq gdebi
— Install gdebi packaage if it is not already installed.
8. Hide your cursor:
tput civis
— Hides cursor.
tput cnorm
— Brings cursor back.
9. Fix a terminal that’s gone crazy:
. .profile
— Reloads your environment.
reset
— resets the terminal completely.
9. Find a command in history:
Ctrl+R
— Activates history search: Start typing to search for text.
Pressing enter without typing will exit search.
— Note: Pessing Ctrl+S will turn off input and output from X!
Press Ctrl+Q to turn it nack on.
10. String commands together at promt as they would run in a script:
command 1; commnad 2; commnad 3; …
— Runs one command after another regardless of any command’s exit code.
11. Change file permissions on entire directory of files:
find /path/to/directory -type f -exec chmod 644 {} \;
— Note: Changing “type -f” to “type -d” will do the same for all directories
in the specified directory.
12. Using ranges in commands:
/bin/df -h /dev/sd[a-z][1-9] 2>/dev/null
— Lists only drive partitions when running the df command.
mkdir test{01..10}
— Creates 10 numbered directories.
13. Catching and dumping unwanted keyboard input (Percy’s patch):
long-running-command; read -t 1 -n 10000 discard