Linux學習之shell 程式設計基礎（一）
一、linux中經常和正則表示式聯合使用的工具
grep
sed
awk（自己去研究吧）.
二，以grep為例，有以下正則操作
| 特殊符號 | 代表意義 |
| [:alnum:] | 代表英文大小寫字元及數字，亦0-9，A-Z，a-z |
| [:alpha:] | 代表任何英文大小寫字元，亦A-Z，a-z |
| [:blank:] | 代表空格鍵與[Tab]按鍵兩者 |
| [:cntrl:] | 代表鍵盤上面的控制按鍵，亦即包括CR、LF、Tab、Del..等等 |
| [:digit:] | 代表數字而已，亦即0-9 |
| [:graph:] | 除了空格符（空格鍵與[Tab]按鍵）外的其他所有按鍵 |
| [:lower:] | 代表小寫字元，亦即a-z |
| [:print:] | 代表任何可以被打印出來的字元 |
| [:punct:] | 代表標點符號（punctuation,symbol),亦即A：" ' ?!;:#$... |
| [:upper:] | 代表大寫字元，亦即A-Z |
| [:space:] | 任何會產生空白的字元，包括空格鍵，[Tab],CR等等 |
| [:xdigit:] | 代表16進位的數字型別，因此包括：0-9,A-F,a-f的數字與字元 |
| RE字元 | 意義與範例 |
| ^word | 意義：待搜尋的字串（word）在行首！ 範例：搜尋行首為#開始的那一行，並列出行號 grep -n '^#' regular_express.txt |
| word$ | 意義：帶搜尋的字串（word）在行尾！ 範例：將行尾為！的那一行打印出來，並列出行號 grep -n '!$' regular_express.txt |
| . | 意義：代表一定有一個任意字元的字元！ 範例：搜尋的字串可以是(eve) (eae) (eee) (e e),但不能僅有(ee) ! 亦即e與e中間一定僅有一個字元，而空格符也是字元！ grep -n 'e.e' reg |
| \ | 意義：跳脫字元，將特殊符號的特殊意義去除！ 範例：搜尋含有單引號'的那一行！ grep -n \' regular_express.txt |
| * | 意義：重複零個到無窮多個的前一個RE字元 範例：找出含有(es)(ess)(esss)等等的字串，注意，因為*可以是0個，所以es也是符合待搜尋字串。另外，因為*為重複前一個RE字元的符號，因此，在*之前必須要緊接著一個RE字元喔！例如任意字元則為 .* |
| [list] | 意義：字元集合的RE字元，裡面列出想要的字元！ 範例：搜尋含有(gl)或(gd)的那一行，需要特別留意的是，在[]當中僅代表一個待搜尋的字元，例如a[afl]y代表搜尋的字串可以是aay,afy,aly即[afl]代表a或f或l的意思！ grep -n 'g[ld]' regular_express.txt |
| [n1-n2] | 意義：字元集合的RE字元，裡面列出想要獲取的字元範圍！ 範例：搜尋含有任意數字的那一行！需特別留意，在字元集合[]中的減號 - 是有特殊意義的，他代表兩個字元之間的所有連續字元！但這個連續與否與ASCII編碼有關，因此，你的編碼需要設定正確（在bash當中，需要確定LANG與LANGUAGE的變數是否正確！） 例如所有大寫字元則為[A-Z] grep -n '[0-9]' regular_express.txt 或 grep -n '[[:digit:]]' regular_express.txt |
| [^list] | 意義：字元集合的RE字元，裡面列出不要的字串或範圍！ 範例：搜尋的字串可以是(oog) (ood) 但不能是(oot),那個^在[]內時，代表的意義是反向選擇的意思。例如，我不要大寫字元，則為[^A-Z]。但是，需要特別注意的是，如果以grep -n [^A-Z] regular_express.txt 來搜尋，卻發現該檔案內的所有行都被列出，為什麼？因為這個[^A-Z]是非大寫字元的意思，因為每一行均有非大寫字元，例如第一行的"Open Source" 就有p,e,n,o...等等的小寫字 grep -n 'oo[^t]' regular_express.txt |
| \{n,m\} | 意義：連續n到m個的前一個RE字元 意義：若為\{n\}則是連續n個的前一個RE字元。 意義：若是\{n,\}則是連續n個以上的前一個RE字元！ 範例：在g與g之間有2個到3個的o存在的字串，亦即（goog）(gooog) grep -n 'go\{2,3\}g' regular_express.txt |
| RE字元 | 意義與範例 |
| + | 意義：重複一個或一個以上的前一個RE字元 範例：搜尋(god)(good)(goood)...等等的字串。那個o+代表一個以上o，所以，底下的執行成果會將1，9，13行列出來。 egrep -n 'go+d' regular_express.txt |
| ？ | 意義：零個或一個的前一個RE字元 範例：搜尋(gd)(god)這兩個字串。那個o?代表空的或1個o，所以，上面的執行成果會將第13，14行列出來。有沒有發現到，這兩個案例('go+d'與’go?d')的結果集合與'go*d'相同？想想看，為啥呢 egrep -n 'go?d' regular_express.txt |
| | | 意義：用或(or)的方法找出數個字串 範例：搜尋gd或good這兩個字串，注意，是或！所以，第1，9，14這三行都可以被打印出來，那如果還想找出dog呢？ egrep -n 'gd|good' regular_express.txt egrep -n 'gd|good|dog' regular_express.txt |
| () | 意義：找出群組字串 範例：搜尋(glad)或(good)這兩個字串，因為g與d是重複的，所以，我就可以將la與oo列於()當中，並以|來分隔開來，就可以啦！ egrep -n 'g(la|oo)d' regular_express.txt |
| ()+ | 意義：多個重複群組的判別 範例：將AxyzxyzxyzxyzC 用echo叫出，然後再使用如下的方法搜尋一下！ echo 'AxyzxyzxyzC'|egrep 'A(xyz)+C' 上面的例子意思是說，我要找開頭是A結尾是C，中間有一個以上的'xyz'字串的意思。 |
三、sed工具
1) 以行為單位的新增/刪除功能
刪除2-5行
[[email protected] ~]$ nl regular_express.txt |sed '2,5d'
1 "Open Source" is a good mechanism to develop programs.
6 GNU is free air not free beer.
7 Her hair is very beauty.
8 I can't finish the test.
9 Oh! The soup taste good.
10 motorcycle is cheap than car.
11 This window is clear.
12 the symbol '*' is represented as start.
13 Oh! My god!
14 The gd software is a library for drafting programs.
15 You are the best is mean you are the no. 1.
16 The world <Happy> is the same with "glad".
17 I like dog.
18 google is the best tools for search keyword.
19 goooooogle yes!
20 go! go! Let's go.
21 # I am VBird
刪除第6行
[[email protected] ~]$ nl regular_express.txt |sed '6d'
1 "Open Source" is a good mechanism to develop programs.
2 apple is my favorite food.
3 Football game is not use feet only.
4 this dress doesn't fit me.
5 However, this dress is about $ 3183 dollars.
7 Her hair is very beauty.
8 I can't finish the test.
9 Oh! The soup taste good.
10 motorcycle is cheap than car.
11 This window is clear.
12 the symbol '*' is represented as start.
13 Oh! My god!
14 The gd software is a library for drafting programs.
15 You are the best is mean you are the no. 1.
16 The world <Happy> is the same with "glad".
17 I like dog.
18 google is the best tools for search keyword.
19 goooooogle yes!
20 go! go! Let's go.
21 # I am VBird
刪除第6行到最後一行
[[email protected] ~]$ nl regular_express.txt |sed '6,$d'
1 "Open Source" is a good mechanism to develop programs.
2 apple is my favorite food.
3 Football game is not use feet only.
4 this dress doesn't fit me.
5 However, this dress is about $ 3183 dollars.
在第二行後（亦即是加在第三行）加上dalianmao字樣
[[email protected] ~]$ nl regular_express.txt |sed '2a dalianmao'
1 "Open Source" is a good mechanism to develop programs.
2 apple is my favorite food.
dalianmao
3 Football game is not use feet only.
4 this dress doesn't fit me.
5 However, this dress is about $ 3183 dollars.
6 GNU is free air not free beer.
7 Her hair is very beauty.
8 I can't finish the test.
9 Oh! The soup taste good.
10 motorcycle is cheap than car.
11 This window is clear.
12 the symbol '*' is represented as start.
13 Oh! My god!
14 The gd software is a library for drafting programs.
15 You are the best is mean you are the no. 1.
16 The world <Happy> is the same with "glad".
17 I like dog.
18 google is the best tools for search keyword.
19 goooooogle yes!
20 go! go! Let's go.
21 # I am VBird
增加三行如下，每行末尾用\分隔
[[email protected] ~]$ nl regular_express.txt |sed '2a dalianmao\
> 23:root\
> 45:fidss\'
1 "Open Source" is a good mechanism to develop programs.
2 apple is my favorite food.
dalianmao\
23:root\
45:fidss
3 Football game is not use feet only.
4 this dress doesn't fit me.
5 However, this dress is about $ 3183 dollars.
6 GNU is free air not free beer.
7 Her hair is very beauty.
8 I can't finish the test.
9 Oh! The soup taste good.
10 motorcycle is cheap than car.
11 This window is clear.
12 the symbol '*' is represented as start.
13 Oh! My god!
14 The gd software is a library for drafting programs.
15 You are the best is mean you are the no. 1.
16 The world <Happy> is the same with "glad".
17 I like dog.
18 google is the best tools for search keyword.
19 goooooogle yes!
20 go! go! Let's go.
21 # I am VBird
注：如果增加在前面，把a換成i即可。
2) 以行為單位的取代與顯示功能
sed [-nefr][動作]
選項與引數：
-n :使用安靜(silent)模式。在一般sed的用法中，所有來自STDIN的資料一般都會被列出到螢幕上。但如果加上-n引數後，則只有經過sed特殊處理的那一行（或者動作）才會被列出來。
-e ：直接在指令列模式上進行sed的動作編輯；
-i ：直接修改讀取的檔案內容，而不是由螢幕輸出。
動作說明：[n1[,n2]]function
n1,n2：不見得會存在，一般代表選擇進行動作的行數，舉例來說，如果我的動作是需要在10到20行之間進行的，則10，20[動作行為]
function有如下這些：
a：新增，a的後面可以接字串，而這些字串會在新的一行出現（目前的下一行）
c：取代，c的後面可以接字串，這些字串可以取代n1,n2之間的行
d：刪除，因為是刪除，所以d後面通常不接任何東西；
i：插入，i的後面可以接字串，而這些字串會在新的一行出現（目前的上一行);
s：取代，可以直接進行取代的工作，通常這個s的動作可以搭配正則表示式，例如'1,20s/old/new/g'就是了，如果new為變數的話，外面用雙引號。
將第2-5 行的內容取代成為 'No 2-5 number'
[[email protected] ~]$ nl regular_express.txt |sed '2,5c No 2-5 number'
1 "Open Source" is a good mechanism to develop programs.
No 2-5 number
6 GNU is free air not free beer.
7 Her hair is very beauty.
8 I can't finish the test.
9 Oh! The soup taste good.
10 motorcycle is cheap than car.
11 This window is clear.
12 the symbol '*' is represented as start.
13 Oh! My god!
14 The gd software is a library for drafting programs.
15 You are the best is mean you are the no. 1.
16 The world <Happy> is the same with "glad".
17 I like dog.
18 google is the best tools for search keyword.
19 goooooogle yes!
20 go! go! Let's go.
21 # I am VBird列出5-7行內容
[[email protected] ~]$ nl regular_express.txt |sed -n '5,7p'
5 However, this dress is about $ 3183 dollars.
6 GNU is free air not free beer.
7 Her hair is very beauty.3) 部分資料的搜尋並取代的功能
sed 's/要被取代的字串/新的字串/g'獲取ip地址
[[email protected] ~]$ /sbin/ifconfig eth0|grep 'inet addr'|sed 's/^.*addr://g'|sed 's/Bcast.*$//g'
192.168.235.129 只要MAN存在的那幾行資料，但是含有#在內的批註我不要，而且空白行也不要
[[email protected] ~]$ cat /etc/man.config |grep 'MAN'|sed 's/#.*$//g'|sed '/^$/d'
MANPATH /usr/man
MANPATH /usr/share/man
MANPATH /usr/local/man
MANPATH /usr/local/share/man
MANPATH /usr/X11R6/man
MANPATH_MAP /bin /usr/share/man
MANPATH_MAP /sbin /usr/share/man
MANPATH_MAP /usr/bin /usr/share/man
MANPATH_MAP /usr/sbin /usr/share/man
MANPATH_MAP /usr/local/bin /usr/local/share/man
MANPATH_MAP /usr/local/sbin /usr/local/share/man
MANPATH_MAP /usr/X11R6/bin /usr/X11R6/man
MANPATH_MAP /usr/bin/X11 /usr/X11R6/man
MANPATH_MAP /usr/bin/mh /usr/share/man
MANSECT 1:1p:8:2:3:3p:4:5:6:7:9:0p:n:l:p:o:1x:2x:3x:4x:5x:6x:7x:8x4)直接修改檔案內容（危險操作！！！！）
將regular_express.txt 內每一行結尾若為.，則換成！
[[email protected] ~]$ sed -i 's/\.$/\!/g' regular_express.txt
[[email protected] ~]$ cat regular_express.txt
"Open Source" is a good mechanism to develop programs!
apple is my favorite food!
Football game is not use feet only!
this dress doesn't fit me!
However, this dress is about $ 3183 dollars.
GNU is free air not free beer.
Her hair is very beauty.
I can't finish the test.
Oh! The soup taste good.
motorcycle is cheap than car!
This window is clear!
the symbol '*' is represented as start!
Oh! My god!
The gd software is a library for drafting programs.
You are the best is mean you are the no. 1!
The world <Happy> is the same with "glad"!
I like dog!
google is the best tools for search keyword!
goooooogle yes!
go! go! Let's go!
# I am VBird利用sed直接在regular_express.txt 最後一行加入 #Hi，dalianmao
[[email protected] ~]$ sed -i '$a # Hi,dalianmao' regular_express.txt
[[email protected] ~]$ cat regular_express.txt
"Open Source" is a good mechanism to develop programs!
apple is my favorite food!
Football game is not use feet only!
this dress doesn't fit me!
However, this dress is about $ 3183 dollars.
GNU is free air not free beer.
Her hair is very beauty.
I can't finish the test.
Oh! The soup taste good.
motorcycle is cheap than car!
This window is clear!
the symbol '*' is represented as start!
Oh! My god!
The gd software is a library for drafting programs.
You are the best is mean you are the no. 1!
The world <Happy> is the same with "glad"!
I like dog!
google is the best tools for search keyword!
goooooogle yes!
go! go! Let's go!
# I am VBird
# Hi,dalianmao注：通過 wget http://linux.vbird.org/linux_basic/0330regularex/regular_express.txt 自行下載文件練習