grep命令 #

#!/bin/bash

# 基本搜索
grep "pattern" file.txt

# 多文件搜索
grep "pattern" *.txt

# 递归搜索
grep -r "pattern" directory/

# 忽略大小写
grep -i "pattern" file.txt

#!/bin/bash

# 基本正则
grep "^start" file.txt      # 以start开头
grep "end$" file.txt        # 以end结尾
grep "a.b" file.txt         # a和b之间任意字符

# 扩展正则
grep -E "a+" file.txt       # 一个或多个a
grep -E "a?" file.txt       # 零个或一个a
grep -E "a|b" file.txt      # a或b

#!/bin/bash

# 查找错误日志
grep -i "error" /var/log/*.log

# 统计匹配行数
grep -c "pattern" file.txt

# 显示上下文
grep -C 3 "pattern" file.txt

# 只显示匹配部分
grep -o "[0-9]\+" file.txt