grep
Created by : Mr Dk.
2022 / 11 / 27 14:17
Hangzhou, Zhejiang, China
Background
grep 用于打印文件中与给定条件匹配的行。
Usage
$ grep --help
Usage: grep [OPTION]... PATTERNS [FILE]...
Search for PATTERNS in each FILE.
Example: grep -i 'hello world' menu.h main.c
PATTERNS can contain multiple patterns separated by newlines.
Pattern selection and interpretation:
-E, --extended-regexp PATTERNS are extended regular expressions
-F, --fixed-strings PATTERNS are strings
-G, --basic-regexp PATTERNS are basic regular expressions
-P, --perl-regexp PATTERNS are Perl regular expressions
-e, --regexp=PATTERNS use PATTERNS for matching
-f, --file=FILE take PATTERNS from FILE
-i, --ignore-case ignore case distinctions in patterns and data
--no-ignore-case do not ignore case distinctions (default)
-w, --word-regexp match only whole words
-x, --line-regexp 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 selected lines
-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 file name with output lines
-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 nonempty parts of lines that match
-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=GLOB search only files that match GLOB (a file pattern)
--exclude=GLOB skip files that match GLOB
--exclude-from=FILE skip files that match any file pattern from FILE
--exclude-dir=GLOB skip directories that match GLOB
-L, --files-without-match print only names of FILEs with no selected lines
-l, --files-with-matches print only names of FILEs with selected lines
-c, --count print only a count of selected 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
--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)
When FILE is '-', read standard input. With no FILE, read '.' if
recursive, '-' otherwise. With fewer than two FILEs, assume -h.
Exit status is 0 if any line (or file if -L) 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: <https://www.gnu.org/gethelp/>
Example
$ cat example.txt
aaa bb cccc
dd e fffff
Output
以下选项影响输出内容。
-v 打印 不匹配 的内容。
-c 参数打印匹配的行数，而不是匹配的行：
$ grep -c bb example.txt
1
-l / -L 打印匹配或不匹配条件的文件名：
$ grep -l bb example.txt
example.txt
-o 只打印匹配的模式串，而不是一整行：
$ grep -o bb example.txt
bb
-n 额外打印匹配上的文件行号：
$ grep -n bb example.txt
1:aaa bb cccc
-A / -B / -C 打印匹配位置的前 / 后 / 前后 N 行：
$ grep -A1 bb example.txt
aaa bb cccc
dd e fffff
Matching
-R 参数递归匹配目录下的所有文件：
$ grep -R -l bb ./
./.oh-my-zsh/tools/upgrade.sh
./.oh-my-zsh/tools/changelog.sh
-i 参数在匹配时忽视大小写：
$ grep -i BB example.txt
aaa bb cccc
-w / -x 只匹配整个词或整行，而不是匹配子串：
$ grep -w b example.txt
$ grep -w bb example.txt
aaa bb cccc
$ grep -x 'bb' example.txt
$ grep -x 'aaa bb cccc' example.txt
aaa bb cccc
grep 实际上可以使用正则表达式进行匹配：
$ grep '^aaa' example.txt
aaa bb cccc
-e 参数指定多个正则表达式：
$ grep -e '^aaa' -e 'f$' example.txt
aaa bb cccc
dd e fffff
也可以直接把正则表达式写到一个文件里，然后通过 -f 参数引用：
$ grep -f pattern.txt example.txt