Single-purpose shell script that uses curl to send messages to Slack via incoming webhooks
Minimal scope: Message delivery only, no complex features or dependencies beyond curl
Lightweight: Designed for integration into bash scripts, cron jobs, and automation pipelines
Maintained by Hansen IT Solutions

Installation

Install curl (if not already present)

# Ubuntu/Debian
sudo apt-get install curl

# macOS
brew install curl

# CentOS/RHEL
sudo yum install curl

Copy script to binary path

sudo cp slackecho /usr/local/bin/
sudo chmod +x /usr/local/bin/slackecho

Configure Slack webhook URL
- Update the SLACKURL variable in the script with your Slack incoming webhook URL
- Create a Slack webhook: https://api.slack.com/messaging/webhooks

Usage

Command Signature

slackecho <message> [username] [channel] [icon]

Parameters

Parameter	Required	Default	Description
`message`	Yes	N/A	Text to send to Slack
`username`	No	`slackecho-user`	Display name of the Slack message sender
`channel`	No	`general`	Target Slack channel (without # prefix)
`icon`	No	`:robot_face:`	Slack emoji icon for the message

Examples

Send a simple message to the default channel:

slackecho "Backup complete"

Send a message with a custom username:

slackecho "Build failed" "CI-Bot"

Send to a specific channel:

slackecho "Deployment complete" "deploy-bot" "deployments"

Use a custom icon:

slackecho "Alert!" "monitoring" "alerts" ":warning:"

Integration Examples

Cron Job

# Report cron job status to Slack
0 2 * * * /path/to/backup.sh && slackecho "Daily backup succeeded" || slackecho "Daily backup failed"

Bash Script

#!/bin/bash
if command -v someapp &> /dev/null; then
    slackecho "someapp is installed" "admin"
else
    slackecho "someapp is NOT installed" "admin" "alerts" ":warning:"
fi

CI/CD Pipeline

# In your CI/CD script
slackecho "Build #${CI_JOB_ID} completed" "CI" "builds"

Configuration

Currently, the webhook URL and default values are hardcoded in the script. Future versions will support:

External configuration file
Environment variables for SLACKURL
Customizable default values per installation

To customize now, edit these variables in the slackecho script:

SLACKURL: Your Slack incoming webhook URL
SLACKUSER: Default username (default: "slackecho-user")
SLACKCH: Default channel (default: "general")
SLACKICON: Default emoji icon (default: ":robot_face:")

Dependencies

curl: For HTTP POST requests to Slack
bash: Shell script runtime

Architecture

The script follows a simple flow:

Validate that at least one argument (message) is provided
Set default values for optional parameters
Build a JSON payload with channel, username, text, and icon_emoji fields
POST the payload to the Slack webhook URL using curl
Suppress output and errors

Testing

Currently no automated tests are in place. Contributions for a lightweight bash test framework (e.g., BATS) are welcome.

To manually test:

./slackecho "Test message" "TestBot" "general"

Error Handling

Currently, the script silently ignores POST failures. Output is suppressed to /dev/null. For debugging:

Comment out the >/dev/null 2>&1 at the end of the curl command
Verify your SLACKURL is correct
Ensure the webhook still exists in your Slack workspace

Contribution Guidelines

Contributions are welcome! Please:

Keep changes minimal and focused on core functionality
Maintain bash compatibility
Test changes before submitting
Follow the existing code style (parameter handling, error suppression)

See TODO for planned improvements.

TODO

Create external configuration file
Support environment variables for SLACKURL
Add bash syntax checking to CI/CD pipeline
Create BATS-based test framework
Implement optional logging
Formalize code review process

Contact

Maintainer: gary@hansenit.solutions
Organization: Hansen IT Solutions