280 Essential Shell Scripts Every Sysadmin Should Use

Shell scripting is a powerful language for automating commands in Linux, enabling batch file processing, tool development, and more.

Below are three practical scripts frequently used by operations engineers.

1. Linux System Alert Script

# yum install mailx
# vi /etc/mail.rc
set [email protected] smtp=smtp.163.com
set [email protected] smtp-auth-password=123456
set smtp-auth=login

2. MySQL Database Backup Loop

#!/bin/bash
DATE=$(date +%F_%H-%M-%S)
HOST=localhost
USER=backup
PASS=123.com
BACKUP_DIR=/data/db_backup
DB_LIST=$(mysql -h $HOST -u $USER -p$PASS -s -e "show databases;" 2>/dev/null | egrep -v "Database|information_schema|mysql|performance_schema|sys")
for DB in $DB_LIST; do
  BACKUP_NAME=$BACKUP_DIR/${DB}_${DATE}.sql
  if ! mysqldump -h $HOST -u $USER -p$PASS -B $DB > $BACKUP_NAME 2>/dev/null; then
    echo "$BACKUP_NAME backup failed!"
  fi
done

3. Real‑time Network Interface Traffic Monitor

#!/bin/bash
NIC=$1
echo -e " In ------ Out"
while true; do
  OLD_IN=$(awk '$0~"'$NIC'"{print $2}' /proc/net/dev)
  OLD_OUT=$(awk '$0~"'$NIC'"{print $10}' /proc/net/dev)
  sleep 1
  NEW_IN=$(awk '$0~"'$NIC'"{print $2}' /proc/net/dev)
  NEW_OUT=$(awk '$0~"'$NIC'"{print $10}' /proc/net/dev)
  IN=$(printf "%.1f%s" "$((($NEW_IN-$OLD_IN)/1024))" "KB/s")
  OUT=$(printf "%.1f%s" "$((($NEW_OUT-$OLD_OUT)/1024))" "KB/s")
  echo "$IN $OUT"
  sleep 1
done