10 Powerful Shell Scripts to Automate System Tasks

Below are ten advanced shell script examples, each solving a different problem or performing a distinct task.

1. Backup Directory

#!/bin/bash

SOURCE_DIR="/path/to/source"
BACKUP_DIR="/path/to/backup"
TIMESTAMP=$(date +"%Y%m%d%H%M%S")

if [ ! -d "$BACKUP_DIR" ]; then
  mkdir -p "$BACKUP_DIR"
fi

tar -czf "$BACKUP_DIR/backup_$TIMESTAMP.tar.gz" -C "$SOURCE_DIR" .
echo "Backup of $SOURCE_DIR completed at $BACKUP_DIR/backup_$TIMESTAMP.tar.gz"

2. Monitor System Resources

#!/bin/bash

LOG_FILE="/var/log/system_monitor.log"
INTERVAL=5

while true; do
  DATE=$(date +"%Y-%m-%d %H:%M:%S")
  CPU=$(top -bn1 | grep "Cpu(s)" | sed "s/.*, *\([0-9.]*\)%* id.*/\1/" | awk '{print 100 - $1"%"}')
  MEM=$(free -m | awk 'NR==2{printf "%.2f%%", $3*100/$2 }')
  DISK=$(df -h | awk '$NF=="/"{printf "%s", $5}')
  echo "$DATE CPU: $CPU, Memory: $MEM, Disk: $DISK" >> $LOG_FILE
  sleep $INTERVAL
done

3. Automatic System Update

#!/bin/bash

sudo apt-get update
sudo apt-get -y upgrade
sudo apt-get -y autoremove
sudo apt-get -y autoclean
echo "System update and cleanup completed."

4. Database Backup

#!/bin/bash

DB_NAME="your_database"
DB_USER="your_username"
DB_PASS="your_password"
BACKUP_DIR="/path/to/backup"
TIMESTAMP=$(date +"%Y%m%d%H%M%S")

mysqldump -u$DB_USER -p$DB_PASS $DB_NAME | gzip > "$BACKUP_DIR/db_backup_$TIMESTAMP.sql.gz"
echo "Database backup completed at $BACKUP_DIR/db_backup_$TIMESTAMP.sql.gz"

5. Automatic FTP Upload

#!/bin/bash

FTP_SERVER="ftp.example.com"
FTP_USER="your_username"
FTP_PASS="your_password"
LOCAL_FILE="/path/to/local/file"
REMOTE_DIR="/path/to/remote/dir"

ftp -inv $FTP_SERVER <<EOF
user $FTP_USER $FTP_PASS
cd $REMOTE_DIR
put $LOCAL_FILE
bye
EOF

echo "File uploaded to $FTP_SERVER:$REMOTE_DIR"

6. Monitor Log File for Keywords

#!/bin/bash

LOG_FILE="/var/log/syslog"
KEYWORD="ERROR"
EMAIL="[email protected]"

tail -Fn0 $LOG_FILE | while read line; do
  echo "$line" | grep "$KEYWORD" &>/dev/null
  if [ $? = 0 ]; then
    echo "$line" | mail -s "Error found in log file" $EMAIL
  fi
done

7. Automatic Report Generation

#!/bin/bash

REPORT_DIR="/path/to/report"
REPORT_FILE="$REPORT_DIR/report_$(date +"%Y%m%d").txt"

if [ ! -d "$REPORT_DIR" ]; then
  mkdir -p "$REPORT_DIR"
fi

echo "Report generated on $(date)" > $REPORT_FILE

echo "==========================" >> $REPORT_FILE
df -h >> $REPORT_FILE
echo "" >> $REPORT_FILE
free -m >> $REPORT_FILE
echo "" >> $REPORT_FILE
uptime >> $REPORT_FILE

echo "Report saved at $REPORT_FILE"

8. Restart Crashed Service

#!/bin/bash

SERVICE_NAME="apache2"
if ! pgrep -x "$SERVICE_NAME" > /dev/null; then
  echo "$SERVICE_NAME is not running. Starting $SERVICE_NAME."
  systemctl start $SERVICE_NAME
else
  echo "$SERVICE_NAME is running."
fi

9. Clean Up Temporary Files

#!/bin/bash

TEMP_DIR="/path/to/temp"
DAYS_OLD=7

find $TEMP_DIR -type f -mtime +$DAYS_OLD -exec rm -f {} \;
echo "Old temporary files deleted."

10. Network Connection Status Monitoring

#!/bin/bash

HOST="8.8.8.8"
LOG_FILE="/var/log/network_status.log"
INTERVAL=10

while true; do
  DATE=$(date +"%Y-%m-%d %H:%M:%S")
  if ping -c 1 $HOST > /dev/null; then
    echo "$DATE Network is up" >> $LOG_FILE
  else
    echo "$DATE Network is down" >> $LOG_FILE
  fi
  sleep $INTERVAL
done

Each script can be adjusted as needed to fit specific environments and requirements.