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:  GNU Grep home page: <>  General help using GNU software: 


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。



note :使用egrep命令,可使用扩展的正则表达式


  • 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|。


  grep -e pattern1 *.py |grep -e pattern2

2.2完全匹配关键词 -w

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


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


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