Linux常用命令之grep命令用法详解

2023-07-21 14:15:03 80

1.官方简介

grep是linux的常用命令，用于对文件和文本执行重复搜索任务的Unix工具，可以通过grep命令指定特定搜索条件来搜索文件及其内容以获取有用的信息。

Usage:grep[OPTION]...PATTERN[FILE]...
SearchforPATTERNineachFILEorstandardinput.
PATTERNis,bydefault,abasicregularexpression(BRE).
Example:grep-i'helloworld'menu.hmain.c

Regexpselectionandinterpretation:
-E,--extended-regexpPATTERNisanextendedregularexpression(ERE)
-F,--fixed-stringsPATTERNisasetofnewline-separatedfixedstrings
-G,--basic-regexpPATTERNisabasicregularexpression(BRE)
-P,--perl-regexpPATTERNisaPerlregularexpression
-e,--regexp=PATTERNusePATTERNformatching
-f,--file=FILEobtainPATTERNfromFILE
-i,--ignore-caseignorecasedistinctions
-w,--word-regexpforcePATTERNtomatchonlywholewords
-x,--line-regexpforcePATTERNtomatchonlywholelines
-z,--null-dataadatalineendsin0byte,notnewline

Miscellaneous:
-s,--no-messagessuppresserrormessages
-v,--invert-matchselectnon-matchinglines
-V,--versiondisplayversioninformationandexit
--helpdisplaythishelptextandexit

Outputcontrol:
-m,--max-count=NUMstopafterNUMmatches
-b,--byte-offsetprintthebyteoffsetwithoutputlines
-n,--line-numberprintlinenumberwithoutputlines
--line-bufferedflushoutputoneveryline
-H,--with-filenameprintthefilenameforeachmatch
-h,--no-filenamesuppressthefilenameprefixonoutput
--label=LABELuseLABELasthestandardinputfilenameprefix
-o,--only-matchingshowonlythepartofalinematchingPATTERN
-q,--quiet,--silentsuppressallnormaloutput
--binary-files=TYPEassumethatbinaryfilesareTYPE;
TYPEis'binary','text',or'without-match'
-a,--textequivalentto--binary-files=text
-Iequivalentto--binary-files=without-match
-d,--directories=ACTIONhowtohandledirectories;
ACTIONis'read','recurse',or'skip'
-D,--devices=ACTIONhowtohandledevices,FIFOsandsockets;
ACTIONis'read'or'skip'
-r,--recursivelike--directories=recurse
-R,--dereference-recursive
likewise,butfollowallsymlinks
--include=FILE_PATTERN
searchonlyfilesthatmatchFILE_PATTERN
--exclude=FILE_PATTERN
skipfilesanddirectoriesmatchingFILE_PATTERN
--exclude-from=FILEskipfilesmatchinganyfilepatternfromFILE
--exclude-dir=PATTERNdirectoriesthatmatchPATTERNwillbeskipped.
-L,--files-without-matchprintonlynamesofFILEscontainingnomatch
-l,--files-with-matchesprintonlynamesofFILEscontainingmatches
-c,--countprintonlyacountofmatchinglinesperFILE
-T,--initial-tabmaketabslineup(ifneeded)
-Z,--nullprint0byteafterFILEname

Contextcontrol:
-B,--before-context=NUMprintNUMlinesofleadingcontext
-A,--after-context=NUMprintNUMlinesoftrailingcontext
-C,--context=NUMprintNUMlinesofoutputcontext
-NUMsameas--context=NUM
--group-separator=SEPuseSEPasagroupseparator
--no-group-separatoruseemptystringasagroupseparator
--color[=WHEN],
--colour[=WHEN]usemarkerstohighlightthematchingstrings;
WHENis'always','never',or'auto'
-U,--binarydonotstripCRcharactersatEOL(MSDOS/Windows)
-u,--unix-byte-offsetsreportoffsetsasifCRswerenotthere
(MSDOS/Windows)

'egrep'means'grep-E'.'fgrep'means'grep-F'.
Directinvocationaseither'egrep'or'fgrep'isdeprecated.
WhenFILEis-,readstandardinput.WithnoFILE,read.ifacommand-line
-risgiven,-otherwise.IffewerthantwoFILEsaregiven,assume-h.
Exitstatusis0ifanylineisselected,1otherwise;
ifanyerroroccursand-qisnotgiven,theexitstatusis2.

Reportbugsto:bug-grep@gnu.org
GNUGrephomepage:
GeneralhelpusingGNUsoftware:http://www.gnu.org/gethelp/

我平时也是简单的查看一个用户数据，用于简单的数据校对，最近突然接到分析后台日志的需求，才发现grep用处还是不少的。

比如我们后台日志相当大，要是直接从服务器直接拉取，耗时长占用带宽，所以方案就是直接使用grep关键字重定向到新的文件中，从14G直接到12M,然后再数据清洗和分析。

2.实战介绍

2.1使用grep命令对多文件中多种文本查询

note:使用egrep命令，可使用扩展的正则表达式

1.多文件

grep'pattern'file1file2

2.多文本，关系是OR

egrep'pattern1|pattern2'*.py
grep-epattern1-epattern2*.py
grep-E'pattern1|pattern2'*.doc

例如下面对对文件中存在关键字wordAorwordB进行提取:

grep'wordA\|wordB'*.py
grep-E'wordA|wordB'*.doc
grep-ewordA-ewordB*.py
egrep"wordA|wordB"*.c

3.多文本关系是AND

这里我并没有看到直接能用的【option】,只能加一层管道符|。

例如：

grep-epattern1*.py|grep-epattern2

2.2完全匹配关键词-w

grep-w'warning\|error\|critical'/home/logs

2.3使用-i参数忽略大小写，–color高亮显示匹配结果

egrep-wi--color'warning|error|critical'/home/logs

2.4递归查找

egrep-Rwi--color'warning|error'/home/logs/

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Linux常用命令之grep命令用法详解

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