grep命令详解（常用参数）

grep命令详解：

grep版本：

# grep -V
grep (GNU grep) 2.20
...

grep --help（或者"man grep"）查看详细语法及参数

语法：
grep [选项]... 模式[文件]...

# grep --help
Usage: grep [OPTION]... PATTERN [FILE]...
Search for PATTERN in each FILE or standard input.
#在每个文件或标准输入中搜索PATTERN。
PATTERN is, by default, a basic regular expression (BRE).
#PATTERN默认为基本正则表达式(basic regular expression, BRE)。
Example: grep -i 'hello world' menu.h main.c
#例如:grep -i 'hello world' menu.h main.c

Regexp selection and interpretation:
#正则表达式的选择和解释:
  -E, --extended-regexp     PATTERN is an extended regular expression (ERE)
  							#模式是一种扩展的常规表达方式
  -F, --fixed-strings       PATTERN is a set of newline-separated fixed strings
  							#模式将样式视为固定字符串的列表,是一组新行分隔的固定字符串
  -G, --basic-regexp        PATTERN is a basic regular expression (BRE)
  							#模式是一个基本的正则表达式(BRE)
  -P, --perl-regexp         PATTERN is a Perl regular expression
  							#模式是一个Perl正则表达式 
  -e, --regexp=PATTERN      use PATTERN for matching
  							#使用PATTERN进行匹配
  -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:
#杂项
  -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: [e-mail]
GNU Grep home page: <http://www.gnu.org/software/grep/>
General help using GNU software: <http://www.gnu.org/gethelp/>
#

grep命令常用示例：（比如在file1文件中搜索error字段）

1、比较两个文件并输出相同部分的内容
grep -wf file1 file2

2、查找某一个字段
(1)、查看文件中某一个字段所在行并显示该行之前10行
grep error -B 10 file1

(2)、查看文件中某一个字段所在行并显示该行之后10行
grep error -A 10 file1

(3)、查看文件中某一个字段所在行并显示该行上下10行
grep error -C 10 file1

3、反向搜索，输出不匹配该字段的行
grep -v error file1

4、显示匹配的字段所在的行号
grep -n error file1

5、匹配多个字段
grep -e error -e successfuled file1

6、使用正则表达式搜索(例子：匹配含有“error”或者“:”和”error:“三种的字符串所在的行)
grep [error:] file1

7、排除多个条件

-E 匹配多个条件
-i 不区分大小写
-v 反向匹配

示例：排除多个条件
grep -Evi 'a|b|c' file_name

示例：匹配多个条件
grep -Ei 'a|b|c' file_name