scripts 1

Bash Script (memorycheck.sh)

memorycheck.sh

#!/bin/bash

# Fetch disk usage percentage for the current directory
space=$(df -h . | tail -1 | awk '{print $(NF-1)}' | tr -d '%')

echo "Consumed disk space is ${space}%"

# Check if disk usage is greater than or equal to 90%
if [ "$space" -ge 90 ]; then
    echo "Disk space is more than 90%. Please take appropriate action." \
    | mail -s "Alert: Disk Space Exceeded 90%" -c "[email protected]" "[email protected]"
fi

Notes

• tr -d '%' is preferred over sed 's/%/ /g' for removing %.

• Wrapped variables in double quotes for safety.

• Added a proper subject for the email alert.

• Improved message readability.

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✅ Cron Job Setup

To run this script every hour at the beginning of the hour, add the following entry to the crontab:

📘 Cron Syntax Breakdown

*     *     *     *     *     command_to_execute
|     |     |     |     |
|     |     |     |     +----- Day of the week (0 - 6) (Sunday=0)
|     |     |     +----------- Month (1 - 12)
|     |     +----------------- Day of the month (1 - 31)
|     +----------------------- Hour (0 - 23)
+----------------------------- Minute (0 - 59)

📌 Cron Examples

Cron Expression	Description
0 * * * *	Every hour at 0 minutes
0 7 22 * *	At 7:00 AM on the 22nd of every month
0 5 * * 1	At 5:00 AM every Monday
5 * * * *	At 5 minutes past every hour
30 14 10 11 *	At 2:30 PM on November 10th
0 */1 * * *	Every hour (same as 0 * * * *)