grep 搜索文本文件中與指定正則表達式匹配的行

grep [OPTIONS] PATTERN [FILE...]

Generic PRogram Information

--help　　打印幫助信息

-V, --version　　打印版本信息

Matcher Selection

-E, --extended-regexp　　使用基本正則表達式（ERE）解釋 PATTERN

-F, --fixed-strings　　每個模式作為一組固定字符串對待（以新行分隔），而不作為正則表達式。

-G, --basic-regexp　　使用基本正則表達式（BRE）解釋 PATTERN

-P, --perl-regexp　　使用 Perl 正則表達式（PCRE）解釋 PATTERN

Matching Control

-e PATTERN, --regexp=PATTERN　　使用 PATTERN 作為匹配模式

-f FILE, --file=FILE　　從文件獲取匹配模式

-i, --ignore-case　　忽略大小寫

-v, --invert-match　　輸出不含匹配項的行

-w, --Word-regexp　　單詞精確匹配

-x, --line-regexp　　行精確匹配

General Output Control

-c, --count　　輸出匹配項的數(shù)目

-l, --files-with-matches　　輸出包含匹配項的文件名而不是直接輸出匹配行

-L, --files-without-match　　與 -l 選項類似，輸出的是包含不匹配項的文件名

-m NUM, --max-count=NUM　　當(dāng)匹配 NUM 后停止讀取文件

-o, --only-matching　　只顯示匹配項而不是匹配行

-q, --quiet, --silent　　安靜模式，不顯示任何信息

-s, --no-messages　　當(dāng)文件不存在或不可讀時，不顯示錯誤信息

Output Line Prefix Control

-b, --byte-offset　　在每個匹配行前加上該行在文件內(nèi)的塊號

-H, --with-filename　　在每個匹配行前加上文件名

-h, --no-filename　　多文件搜索時，抑制文件名輸出

-n, --line-number　　在每個匹配行前加上該行在文件內(nèi)的行號

Context Line Control

-A NUM, --after-context=NUM　　輸出匹配行及其后 NUM 行的內(nèi)容

-B NUM, --before-context=NUM　　輸出匹配行及其前 NUM 行的內(nèi)容

-C NUM, -NUM, --context=NUM　　輸出匹配行及其前后 NUM 行的內(nèi)容

測試文件 test.txt：

The Zen of Python, by Tim PetersBeautiful is better than uglyExplicit is better than implicitSimple is better than complexComplex is better than complicatedFlat is better than nestedSparse is better than denseReadability countsSpecial cases aren't special enough to break the rulesAlthough practicality beats purityErrors should never pass silentlyUnless explicitly silencedIn the face of ambiguity, refuse the temptation to guessThere should be one-- and preferably only one --obvious way to do itAlthough that way may not be obvious at first unless you're DutchNow is better than neverAlthough never is often better than *right* nowIf the implementation is hard to explain, it's a bad ideaIf the implementation is easy to explain, it may be a good ideaNamespaces are one honking great idea -- let's do more of those

a) 輸出含有 "com" 的行

huey@huey-K42JE:~/huey/linux/cmdline$ grep com test.txtSimple is better than complexComplex is better than complicated

b) 匹配時忽略大小寫

huey@huey-K42JE:~/huey/linux/cmdline$ grep -i com test.txtSimple is better than complexComplex is better than complicated

c) 輸出以 "complex" 開頭的行，忽略大小寫

huey@huey-K42JE:~/huey/linux/cmdline$ grep -i '^complex' test.txtComplex is better than complicated

d) 輸出以 "idea" 結(jié)尾的行

huey@huey-K42JE:~/huey/linux/cmdline$ grep 'idea$' test.txtIf the implementation is hard to explain, it's a bad ideaIf the implementation is easy to explain, it may be a good idea

e) 匹配空行

huey@huey-K42JE:~/huey/linux/cmdline$ grep -n '^$' test.txt2:

h) 輸出含有 "good" 或 "bad" 的行

huey@huey-K42JE:~/huey/linux/cmdline$ grep 'good/|bad' test.txtIf the implementation is hard to explain, it's a bad ideaIf the implementation is easy to explain, it may be a good ideahuey@huey-K42JE:~/huey/linux/cmdline$ grep -E 'good|bad' test.txtIf the implementation is hard to explain, it's a bad ideaIf the implementation is easy to explain, it may be a good idea

i) 精確匹配單詞 it，像 implicit、purity、purity 等這樣的單詞中的 it 部分是不會被匹配的

huey@huey-K42JE:~/huey/linux/cmdline$ grep -w it test.txtThere should be one-- and preferably only one --obvious way to do itIf the implementation is hard to explain, it's a bad ideaIf the implementation is easy to explain, it may be a good idea

j) 輸出含有 "Python" 的行及其后 3 行

huey@huey-K42JE:~/huey/linux/cmdline$ grep -A 3 Python test.txtThe Zen of Python, by Tim PetersBeautiful is better than uglyExplicit is better than implicit

egrep - 相當(dāng)于 grep -E

fgrep - 相當(dāng)于 grep -F

pgrep - 相當(dāng)于 grep -P