linux通过grep根据关键字查找日志文件上下文

1、在标准unix/linux下的grep命令中，通过以下参数控制上下文的显示：

grep -C 10 keyword catalina.out 显示file文件中匹配keyword字串那行以及上下10行

grep -B 10 keyword catalina.out 显示keyword及前10行

grep -A 10 keyword catalina.out 显示keyword及后10行

2、查找的结果比较大时，为了方便定位问题，也可以重定向到文件中，比如：

grep -C 10 keyword catalina.out  > aaa.txt

3、统计包含某个关键字的个数

grep -o keyword catalina.out| wc -l

4、如果一行最多一个关键字，可以简写为：

grep -c keyword catalina.out

5、查看grep版本的方法是

grep -V

Grep命令详细说明：

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: [email protected]GNU Grep home page: General help using GNU software: