每天一個Linux命令（34）grep命令

[b] grep（global search regular expression(RE) and print out the line，全面搜索正則表達式並把行打印出來）是一種強大的文本搜索工具，它能使用正則表達式搜索文本，並把匹配的行打印出來。[/b][b] (1)用法:[/b]

[b] 用法: grep [選項]... PATTERN [FILE]...[/b][b] (2)功能:[/b]

[b] 功能: 在每個 FILE 或是標准輸入中查找 PATTERN。[/b][b] (3)選項參數:[/b]

1) -V, --version 　　　　　　　　　　顯示版本號

2) -i　　　　　　　　　　　　　　　　在匹配過程中忽略大小寫

3) -v, --invert-match 　　　　　　　 顯示不匹配的行 4) -f　　　　　　　　　　　　　　　　指定文件中存的每行字符串作為匹配字符串

5) -c　　　　　　　　　　　　　　　　統計每個文件中包含指定字符串的行數 6) --color=auto　　　　　　　　　　 標記匹配顏色

7) -E 　　　　　　　　　　　　　　　 將范本樣式為延伸的普通表示法來使用，意味著使用能使用擴展正則表達式

8) -q　　　　　　　　　　　　　　　　 grep靜默輸出，常用來測試。[b] (4)實例:[/b]

1)[root@localhost grepDir]# grep "MenAngel" t1.txt t2.txt t3.txt　　　　　　　　　　在特定的文本集中查找特定字符串

[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!

2)[root@localhost grepDir]# grep -v "MenAngel" t1.txt t2.txt t3.txt　　　　　　　　輸出指定字符串所在行之外的所有文件的行內容

[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.

3)[root@localhost grepDir]# grep "fight" t1.txt t2.txt t3.txt --color=auto　　　　　 將查找的字符串用特定的顏色標記出來

[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!

4)[root@localhost grepDir]# grep -c "that" t1.txt t2.txt t3.txt　　　　　　　　　　　 統計每個文件中包含指定字符串的行數

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

5)[root@localhost grepDir]# grep -n "that" t1.txt t2.txt t3.txt　　　　　　　　　　 默認情況，輸出包含特定字符串所在的行

[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  //沒有以M開頭的
[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這裡處理的是前面的echo輸出的內容
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 [選項]... PATTERN [FILE]...
在每個 FILE 或是標准輸入中查找 PATTERN。
默認的 PATTERN 是一個基本正則表達式(縮寫為 BRE)。
例如: grep -i 'hello world' menu.h main.c

正則表達式選擇與解釋:
  -E, --extended-regexp     PATTERN 是一個可擴展的正則表達式(縮寫為 ERE)
  -F, --fixed-strings       PATTERN 是一組由斷行符分隔的定長字符串。
  -G, --basic-regexp        PATTERN 是一個基本正則表達式(縮寫為 BRE)
  -P, --perl-regexp         PATTERN 是一個 Perl 正則表達式
  -e, --regexp=PATTERN      用 PATTERN 來進行匹配操作
  -f, --file=FILE           從 FILE 中取得 PATTERN
  -i, --ignore-case         忽略大小寫
  -w, --word-regexp         強制 PATTERN 僅完全匹配字詞
  -x, --line-regexp         強制 PATTERN 僅完全匹配一行
  -z, --null-data           一個 0 字節的數據行，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

輸出控制:
  -m, --max-count=NUM       NUM 次匹配後停止
  -b, --byte-offset         輸出的同時打印字節偏移
  -n, --line-number         輸出的同時打印行號
      --line-buffered       每行輸出清空
  -H, --with-filename       為每一匹配項打印文件名
  -h, --no-filename         輸出時不顯示文件名前綴
      --label=LABEL         將LABEL 作為標准輸入文件名前綴
  -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   打印以文本結尾的NUM 行
  -C, --context=NUM         打印輸出文本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 為 -，將讀取標准輸入。不帶FILE，讀取當前目錄，除非命令行中指定了-r 選項。
如果少於兩個FILE 參數，就要默認使用-h 參數。
如果有任意行被匹配，那退出狀態為 0，否則為 1；
如果有錯誤產生，且未指定 -q 參數，那退出狀態為 2。

請將錯誤報告給: [email protected]
GNU Grep 主頁: <http://www.gnu.org/software/grep/>
GNU 軟件的通用幫助: <http://www.gnu.org/gethelp/>