echo "Hello World" > test.txt
echo "hello python" >> test.txt
echo "big apple" >> test.txt
echo "key1" >> test.txt
echo "code99" >> test.txt
区分大小写
grep "Hello" test.txt
Hello World
不区分大小写
grep -i "Hello" test.txt
Hello World
hello python
只显示以’h’开头的文本行
grep "^h" test.txt
hello python
检索以’e’结尾的文本格式
grep -i "e$" test.txt
big apple
搜索空白行
grep '^$' test.txt
匹配 ‘Hello’ 或 ‘hello’
grep "[Hh]ello" test.txt
Hello World
hello python
匹配数字
grep "y[0-9]" test.txt
key1
以匹配两位数
grep "e[0-9][0-9]" test.txt
code99
匹配字母
grep '[A-Za-z]' test.txt
Hello World
hello python
big apple
key1
code99
显示所有包含 “p” 或 “y” 字母的文本行
grep '[py]'' test.txt
hello python
big apple
key1
匹配包含两个字母’p’的字符串结果
egrep "p{2}" test.txt
big apple
检索文件内包含’p’和’pp’的字符串结果
egrep "p{1,2}" test.txt
hello python
big apple
匹配至少含有3个字母’p’的结果
egrep "p{3,}" test.txt
从文件读入多个匹配模式
echo "y1" > p.txt
echo "d$" >> p.txt
grep -f p.txt test.txt
Hello World
key1
