Showing a GUI Notification From a Shell Script in Linux

GUI notifications from shell scripts in Linux allow you to display visual alerts and messages to users. Two primary tools accomplish this: notify-send for desktop notifications and zenity for interactive dialog boxes.

Using the notify-send Command

The notify-send command is part of the libnotify library and comes pre-installed on most Linux distributions. It displays brief desktop notifications that appear in the system notification area.

Basic Syntax

notify-send [options] <title> <message>

Simple example displaying a notification

notify-send "Hello" "World"

Common Options

Advanced notification example

notify-send -u critical -t 5000 -i dialog-warning "System Alert" "Disk space is running low"

Notifications in Shell Scripts

Basic shell script with notification

#!/bin/bash

# Script commands here
echo "Processing files..."
sleep 3

# Send completion notification
notify-send "Script Complete" "File processing finished successfully"

Using variables for dynamic notifications

#!/bin/bash

# Define notification content
title="Backup Status"
message="Backup completed at $(date)"

# Send notification
notify-send "$title" "$message"

Conditional Notifications

#!/bin/bash

# Simulate a task
if some_command; then
    notify-send -u normal "Success" "Task completed successfully"
else
    notify-send -u critical "Error" "Task failed to complete"
fi

Using the zenity Utility

Zenity displays GTK+ dialog boxes and is ideal for interactive notifications that require user input. It provides more visual options than notify-send.

Dialog Types

Information dialog

zenity --info --title="Information" --text="Process completed successfully"

Warning dialog

zenity --warning --title="Warning" --text="System resources are low"

Error dialog

zenity --error --title="Error" --text="Failed to connect to server"

Question dialog with user input

if zenity --question --title="Confirm" --text="Do you want to continue?"; then
    echo "User selected Yes"
else
    echo "User selected No"
fi

Advanced zenity Examples

Text entry dialog

name=$(zenity --entry --title="User Input" --text="Enter your name:")
echo "Hello, $name"

Progress bar notification

(for i in {1..100}; do 
    echo $i
    sleep 0.1
done) | zenity --progress --title="Processing" --text="Please wait..." --auto-close

File selection dialog

file=$(zenity --file-selection --title="Select File" --file-filter="Text files | *.txt")
echo "Selected file: $file"

Comparison

Conclusion

Both notify-send and zenity provide effective ways to display GUI notifications from shell scripts. Use notify-send for simple status notifications and zenity when you need user interaction or more complex dialog functionality. Choose the appropriate tool based on whether you need passive notifications or active user engagement.