Script for making updates to /etc/environment file. Includes various safeguards, and records of all changes

safe-edit-global-env-file.sh

#!/bin/bash

# Define the name of the revised environment file.
REVISED_ENV_FILE='e.sh'

# Check if REVISED_ENV_FILE exists, if not, execute the following commands.
if [ ! -f "$REVISED_ENV_FILE" ]; then
    # Copy the default system environment file to the revised file.
    cp /etc/environment "$REVISED_ENV_FILE"

    # Back up the revised file as environment.bak with sudo privileges.
    sudo cp "$REVISED_ENV_FILE" environment.bak

    # Create an additional backup with a dot prefix and gzip it.
    sudo cp environment.bak .environment.bak
    sudo gzip .environment.bak

    # Set read-only permissions for environment.bak.
    sudo chmod 444 environment.bak
fi

# Assign the current directory of this script to 'HERE' variable.
HERE="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"

# Navigate to the directory stored in 'HERE' or exit with an error code.
cd "$HERE" || exit 1

# Store the current date and time as a timestamp.
TIMESTAMP="$(date +%s)"

# Create a timestamped backup of current /etc/environment in /tmp.
sudo cp /etc/environment "/tmp/etc.environment.bak.${TIMESTAMP}"

# Ensure the data directory exists and define ENV_FILE path using TIMESTAMP.
mkdir -p ./data
ENV_FILE="./data/env.${TIMESTAMP}"

# Copy the revised environment file to a new file with 'new' suffix.
sudo cp "$REVISED_ENV_FILE" "$ENV_FILE.new"

# Create an old backup of the environment file with 'old' suffix and set its permissions to read-only.
sudo cp /etc/environment "$ENV_FILE.old" && sudo chmod 444 "$ENV_FILE.old"

# Replace the current system environment file with our revised file.
sudo cp -fv "$ENV_FILE.new" /etc/environment

# Restore system environment file's permissions to owner read/write and group/others read.
sudo chmod 644 /etc/environment

# Set the revised file's permissions to read-only.
sudo chmod 444 "$ENV_FILE.new"

# Print out section headers and content of the old, new, and system environment files using bat command.
echo '
-----------------------------------------------
-                old                          -
-----------------------------------------------'
bat -l sh -P --plain -f "$ENV_FILE.old"
echo '
-----------------------------------------------
-                new                          -
-----------------------------------------------'
bat -l sh -P --plain -f "$ENV_FILE.new"

echo '
-----------------------------------------------
-                 /etc/environment            -
-----------------------------------------------'
bat -l sh -P --plain -f /etc/environment