Linux常用命令之grep命令用法详解
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2022-03-16 19:22:41
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 [optio...
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]... search for pattern in each file or standard input. pattern is, by default, a basic regular expression (bre). example: grep -i 'hello world' menu.h main.c regexp selection and interpretation: -e, --extended-regexp pattern is an extended regular expression (ere) -f, --fixed-strings pattern is a set of newline-separated fixed strings -g, --basic-regexp pattern is a basic regular expression (bre) -p, --perl-regexp pattern is a perl regular expression -e, --regexp=pattern use pattern for matching -f, --file=file obtain pattern from file -i, --ignore-case ignore case distinctions -w, --word-regexp force pattern to match only whole words -x, --line-regexp force pattern to match only whole lines -z, --null-data a data line ends in 0 byte, not newline miscellaneous: -s, --no-messages suppress error messages -v, --invert-match select non-matching lines -v, --version display version information and exit --help display this help text and exit output control: -m, --max-count=num stop after num matches -b, --byte-offset print the byte offset with output lines -n, --line-number print line number with output lines --line-buffered flush output on every line -h, --with-filename print the file name for each match -h, --no-filename suppress the file name prefix on output --label=label use label as the standard input file name prefix -o, --only-matching show only the part of a line matching pattern -q, --quiet, --silent suppress all normal output --binary-files=type assume that binary files are type; type is 'binary', 'text', or 'without-match' -a, --text equivalent to --binary-files=text -i equivalent to --binary-files=without-match -d, --directories=action how to handle directories; action is 'read', 'recurse', or 'skip' -d, --devices=action how to handle devices, fifos and sockets; action is 'read' or 'skip' -r, --recursive like --directories=recurse -r, --dereference-recursive likewise, but follow all symlinks --include=file_pattern search only files that match file_pattern --exclude=file_pattern skip files and directories matching file_pattern --exclude-from=file skip files matching any file pattern from file --exclude-dir=pattern directories that match pattern will be skipped. -l, --files-without-match print only names of files containing no match -l, --files-with-matches print only names of files containing matches -c, --count print only a count of matching lines per file -t, --initial-tab make tabs line up (if needed) -z, --null print 0 byte after file name context control: -b, --before-context=num print num lines of leading context -a, --after-context=num print num lines of trailing context -c, --context=num print num lines of output context -num same as --context=num --group-separator=sep use sep as a group separator --no-group-separator use empty string as a group separator --color[=when], --colour[=when] use markers to highlight the matching strings; when is 'always', 'never', or 'auto' -u, --binary do not strip cr characters at eol (msdos/windows) -u, --unix-byte-offsets report offsets as if crs were not there (msdos/windows) 'egrep' means 'grep -e'. 'fgrep' means 'grep -f'. direct invocation as either 'egrep' or 'fgrep' is deprecated. when file is -, read standard input. with no file, read . if a command-line -r is given, - otherwise. if fewer than two files are given, assume -h. exit status is 0 if any line is selected, 1 otherwise; if any error occurs and -q is not given, the exit status is 2. report bugs to: bug-grep@gnu.org gnu grep home page: <http://www.gnu.org/software/grep/> general help using gnu software: 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' file1 file2
2.多文本 , 关系是or
- egrep 'pattern1|pattern2' *.py
- grep -e pattern1 -e pattern2 *.py
- grep -e 'pattern1|pattern2' *.doc
例如下面对 对文件中 存在关键字 worda or wordb进行提取:
grep 'worda\|wordb' *.py grep -e 'worda|wordb' *.doc grep -e worda -e wordb *.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 -e pattern1 *.py |grep -e pattern2
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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