Shell Scripting Tips & Tricks

March 08, 2021

Collection of shell and bash snippets.

Error Handling

# Disable exit on non 0. Continue if script fails
set +e

#Enable exit on non 0. Stop if script fails
set -e

Trace in Scripts

# Helps debug code as it executes
set -xv

Packaging & Un-Packaging

# open a .bz2 file
bzip2 -dc my_file.tar.bz2 | tar xvf -

Untar contents into a folder

mkdir helm
tar -zxvf helm-v3.8.1-linux-amd64.tar.gz -C helm --strip-components=1

Password Management

Set initial password

echo -e "linuxpassword\nlinuxpassword" | passwd linuxuser

Set Password for remote servers

for ((i=1;i<=100;i++)); do \
ssh 192.168.1.10$i 'echo -e "linuxpassword\nlinuxpassword" | passwd linuxuser'; \
done;

Create user and set password

useradd newuser; echo -e "passwdofuser\npasswdofuser" | passwd newuser

Get folder of current directory

Print out the value of the folder of the current working directory

echo $(basename "$PWD")