每天一个Linux命令（34）grep命令

[root@localhost grepDir]# cat >t1.txt
I'm MenAngel!
Although I'm still a poor student right now,I believe that someday I will be one of the successful man in the world!
^Z
[3]+  已停止               cat > t1.txt
[root@localhost grepDir]# cat >t2.txt
Every one fights for a better future,but I fight for freedom!
^Z
[4]+  已停止               cat > t2.txt
[root@localhost grepDir]# cat >t3.txt <<EOF
> There is no one hoping that you will succeed when you are been looking down upon,but if you succeeded,they will look down upon themselves!
> When you get an important thing,you will find that it is not so precious as you like,but when you lose it after that,it will become so precious as you liked.
> EOF
[root@localhost grepDir]# grep "MenAngel" t1.txt t2.txt t3.txt
t1.txt:I'm MenAngel!

[root@localhost grepDir]# grep -v "MenAngel" t1.txt t2.txt t3.txt
t1.txt:Although I'm still a poor student right now,I believe that someday I will be one of the successful man in the world!
t2.txt:Every one fights for a better future,but I fight for freedom!
t3.txt:There is no one hoping that you will succeed when you are been looking down upon,but if you succeeded,they will look down upon themselves!
t3.txt:When you get an important thing,you will find that it is not so precious as you like,but when you lose it after that,it will become so precious as you liked.

[root@localhost grepDir]# grep "fight" t1.txt t2.txt t3.txt --color=auto
t2.txt:Every one fights for a better future,but I fight for freedom!

[root@localhost grepDir]# grep -c "that" t1.txt t2.txt t3.txt
t1.txt:1
t2.txt:0
t3.txt:2

[root@localhost grepDir]# grep -n "that" t1.txt t2.txt t3.txt
t1.txt:2:Although I'm still a poor student right now,I believe that someday I will be one of the successful man in the world!
t3.txt:1:There is no one hoping that you will succeed when you are been looking down upon,but if you succeeded,they will look down upon themselves!
t3.txt:2:When you get an important thing,you will find that it is not so precious as you like,but when you lose it after that,it will become so precious as you liked.
[root@localhost grepDir]# grep "that" t1.txt t2.txt t3.txt
t1.txt:Although I'm still a poor student right now,I believe that someday I will be one of the successful man in the world!
t3.txt:There is no one hoping that you will succeed when you are been looking down upon,but if you succeeded,they will look down upon themselves!
t3.txt:When you get an important thing,you will find that it is not so precious as you like,but when you lose it after that,it will become so precious as you liked.

[root@localhost grepDir]# cat t1.txt t2.txt t3.txt|grep "MenAngel"
I'm MenAngel!
[root@localhost grepDir]# grep "MenAngel" t1.txt t2.txt t3.txt
t1.txt:I'm MenAngel!

[root@localhost grepDir]# cat t1.txt t2.txt t3.txt|grep ^I
I'm MenAngel!
[root@localhost grepDir]# cat t1.txt t2.txt t3.txt|grep ^M  //没有以M开头的
[root@localhost grepDir]#

[root@localhost grepDir]# cat t1.txt t2.txt t3.txt|grep ^[^I]
Although I'm still a poor student right now,I believe that someday I will be one of the successful man in the world!
Every one fights for a better future,but I fight for freedom!
There is no one hoping that you will succeed when you are been looking down upon,but if you succeeded,they will look down upon themselves!
When you get an important thing,you will find that it is not so precious as you like,but when you lose it after that,it will become so precious as you liked.
[root@localhost grepDir]#

[root@localhost grepDir]# seq 10|grep "5" -C 3
2
3
4
5
6
7
8
[root@localhost grepDir]# seq 10|grep "5" -A 3
5
6
7
8
[root@localhost grepDir]# seq 10|grep "5" -B 3
2
3
4
5

[root@localhost grepDir]# grep -C 3 "MenAngel" t1.txt t2.txt t3.txt
t1.txt:I'm MenAngel!
t1.txt-Although I'm still a poor student right now,I believe that someday I will be one of the successful man in the world!

[root@localhost grepDir]# echo -e "a\nb\nc\na\nb\nc" | grep a -A 1
a
b
--
a
b
[root@localhost grepDir]#
[root@localhost grepDir]# echo -e "a\nb\nc\nd\na\nb\nc\nd" | grep a -A 1
a
b
--
a
b
[root@localhost grepDir]# echo -e "a\nb\nc\nd\na\nb\nc\nd" | grep a -A 2
a
b
c
--
a
b
c

[root@localhost grepDir]# echo this is a text line | grep -e "is" -e "line" -o   //grep这里处理的是前面的echo输出的内容
is
is
line

[root@localhost grepDir]# cat >patfile <<EOF
> MenAngel
> sunjimeng
> EOF
[root@localhost grepDir]# echo MenAngel is sunjimeng|grep -f patfile
MenAngel is sunjimeng
[root@localhost grepDir]#

[root@localhost grepDir]# grep --help
用法: grep [选项]... PATTERN [FILE]...
在每个 FILE 或是标准输入中查找 PATTERN。
默认的 PATTERN 是一个基本正则表达式(缩写为 BRE)。
例如: grep -i 'hello world' menu.h main.c

正则表达式选择与解释:
-E, --extended-regexp     PATTERN 是一个可扩展的正则表达式(缩写为 ERE)
-F, --fixed-strings       PATTERN 是一组由断行符分隔的定长字符串。
-G, --basic-regexp        PATTERN 是一个基本正则表达式(缩写为 BRE)
-P, --perl-regexp         PATTERN 是一个 Perl 正则表达式
-e, --regexp=PATTERN      用 PATTERN 来进行匹配操作
-f, --file=FILE           从 FILE 中取得 PATTERN
-i, --ignore-case         忽略大小写
-w, --word-regexp         强制 PATTERN 仅完全匹配字词
-x, --line-regexp         强制 PATTERN 仅完全匹配一行
-z, --null-data           一个 0 字节的数据行，但不是空行

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

输出控制:
-m, --max-count=NUM       NUM 次匹配后停止
-b, --byte-offset         输出的同时打印字节偏移
-n, --line-number         输出的同时打印行号
--line-buffered       每行输出清空
-H, --with-filename       为每一匹配项打印文件名
-h, --no-filename         输出时不显示文件名前缀
--label=LABEL         将LABEL 作为标准输入文件名前缀
-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

文件控制:
-B, --before-context=NUM  打印以文本起始的NUM 行
-A, --after-context=NUM   打印以文本结尾的NUM 行
-C, --context=NUM         打印输出文本NUM 行
-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’即‘grep -E’。‘fgrep’即‘grep -F’。
直接使用‘egrep’或是‘fgrep’均已不可行了。
若FILE 为 -，将读取标准输入。不带FILE，读取当前目录，除非命令行中指定了-r 选项。
如果少于两个FILE 参数，就要默认使用-h 参数。
如果有任意行被匹配，那退出状态为 0，否则为 1；
如果有错误产生，且未指定 -q 参数，那退出状态为 2。

请将错误报告给: bug-grep@gnu.org
GNU Grep 主页: <http://www.gnu.org/software/grep/>
GNU 软件的通用帮助: <http://www.gnu.org/gethelp/>