From the Linux Terminal to Shell Scripts

James Scott Programming

Once you are comfortable typing commands, shell scripts let you automate backups, deployments, and file chores. Bash is the default shell on Ubuntu — scripts are plain text files executed by the terminal.

Your first script

#!/bin/bash
echo "Hello from $(hostname)"
date >> ~/script-log.txt

Save as hello.sh, run chmod +x hello.sh, then ./hello.sh. The #!/bin/bash line tells Linux which interpreter to use.

Variables and input

NAME="Dave"
echo "Backup starting for $NAME"
read -p "Continue? (y/n) " ANSWER

Conditionals and loops

if [ -f /etc/hosts ]; then
  cp /etc/hosts ~/hosts.backup
fi

for file in *.log; do
  gzip "$file"
done

Best practices

  • Use set -e to exit on errors in production scripts.
  • Quote variables: "$VAR" handles spaces safely.
  • Test with shellcheck script.sh after installing ShellCheck via APT.
  • Schedule recurring jobs with cron or systemd timers.

Scripts bridge manual terminal work and full applications. Start small — automate one annoying task this week, then combine scripts into larger workflows as you grow.