149 Essential Shell Scripts for Sysadmins – Keep Them Handy

The author shares a selection of useful Bash scripts that can help Linux system administrators automate repetitive tasks and improve efficiency. The full set contains 149 scripts across 68 pages, searchable by keyword; the article shows a representative subset.

1. Find zombie processes

#!/bin/bash
# 查找 Linux 系统中的僵尸进程
# awk 判断 ps 命令输出的第 8 列为 Z 是,显示该进程的 PID 和进程命令
ps aux | awk '{if($8 == "Z"){print $2,$11}}'

2. Delete zero‑size files in a directory

#!/bin/bash
# 删除某个目录下大小为 0 的文件
#/var/www/html 为测试目录,脚本会清空该目录下所有 0 字节的文件

dir="/var/www/html"
find $dir -type f -size 0 -exec rm -rf {} \;

3. Read five numbers (<100) and compute sum, min, max

#!/bin/bash
COUNT=1
SUM=0
MIN=0
MAX=100
while [ $COUNT -le 5 ]; do
  read -p "请输入1-10个整数：" INT
  if [[ ! $INT =~ ^[0-9]+$ ]]; then
    echo "输入必须是整数！"
    exit 1
  elif [[ $INT -gt 100 ]]; then
    echo "输入必须是100以内！"
    exit 1
  fi
  SUM=$((SUM+INT))
  [ $MIN -lt $INT ] && MIN=$INT
  [ $MAX -gt $INT ] && MAX=$INT
  let COUNT++
done
echo "SUM: $SUM"
echo "MIN: $MIN"
echo "MAX: $MAX"

4. Print various date/time formats

#!/bin/bash
# 打印各种时间格式

echo "显示星期简称(如:Sun)"
date +%a

echo "显示星期全称(如:Sunday)"
date +%A

echo "显示月份简称(如:Jan)"
date +%b

echo "显示月份全称(如:January)"
date +%B

echo "显示数字月份(如:12)"
date +%m

echo "显示数字日期(如:01)"
date +%d

echo "显示数字年(如:2023)"
date +%Y

echo "显示年‑月‑日"
date +%F

echo "显示小时(24 小时制)"
date +%H

echo "显示分钟(00..59)"
date +%M

echo "显示秒"
date +%S

echo "显示纳秒"
date +%N

echo "组合显示"
date +"%Y%m%d %H:%M:%S"

5. Check if a file or directory exists

#!/bin/bash
# 判断文件或目录是否存在
if [ $# -eq 0 ]; then
  echo "未输入任何参数,请输入参数"
  echo "用法: $0 [文件名|目录名]"
fi

if [ -f $1 ]; then
  echo "该文件,存在"
  ls -l $1
else
  echo "没有该文件"
fi

if [ -d $2 ]; then
  echo "该目录,存在"
  ls -ld $2
else
  echo "没有该目录"
fi

6. Sort three input integers

#!/bin/bash
# 依次提示用户输入 3 个整数,脚本根据数字大小依次排序输出 3 个数字
read -p " 请输⼊⼀个整数：" num1
read -p " 请输⼊⼀个整数：" num2
read -p " 请输⼊⼀个整数: " num3

tmp=0
if [ $num1 -gt $num2 ]; then
  tmp=$num1
  num1=$num2
  num2=$tmp
fi
if [ $num1 -gt $num3 ]; then
  tmp=$num1
  num1=$num3
  num3=$tmp
fi
if [ $num2 -gt $num3 ]; then
  tmp=$num2
  num2=$num3
  num3=$tmp
fi

echo "排序后数据（从⼩到⼤）为： $num1, $num2, $num3"

7. Get local MAC address

#!/bin/bash
# 获取本机 MAC 地址
ip a s | awk 'BEGIN{print " 本 机 MAC 地 址 信 息 如 下 :"}/^[0-9]/{print $2;getline;if($0~/link\/ether/){print $2}}' | grep -v lo:

8. Determine if a year is a leap year

#!/bin/bash
# 提示用户输入年份后判断该年是否为闰年
# 能被4整除并且不能被100整除的年份是闰年
# 能被400整除的年份也是闰年
read -p "请输入一个年份:" year
if [ "$year" = "" ]; then
  echo "没有输入年份"
  exit 1
fi
if [[ "$year" =~ [a‑Z] ]]; then
  echo "你输入的不是数字"
  exit 1
fi
if [ $((year % 4)) -eq 0 ] && [ $((year % 100)) -ne 0 ]; then
  echo "$year 年是闰年"
elif [ $((year % 400)) -eq 0 ]; then
  echo "$year 年是闰年"
else
  echo "$year 年不是闰年"
fi

These examples illustrate typical sysadmin tasks and can be copied directly into a Bash environment. The full collection includes many more scripts covering file manipulation, system monitoring, network queries, and automation patterns useful for daily operations.