shell sed 字串替換

2022-02-01 08:02:41 字數 3004 閱讀 6442

content

macname@localhost desktop %macname@localhost desktop %cat ddd


this 


isa test of the test script.


this 


isthe second test of the test script.


macname@localhost desktop %

#在行中替換文字

macname@localhost desktop % sed '


s/test/trial/


'ddd


this 


isa trial of the test script.


this 


isthe second trial of the test script.


macname@localhost desktop %

#指定sed編輯器用新文字替換第幾處模式匹配的地方

macname@localhost desktop %macname@localhost desktop % sed '


s/test/trial/2


'ddd


this 


isa test of the trial script.


this 


isthe second test of the trial script.


macname@localhost desktop %

將替換標記指定為2的結果就是:sed編輯器只替換每行中第二次出現的匹配模式。

g替換標 記使你能替換文字中匹配模式所匹配的每處地方

macname@localhost desktop %macname@localhost desktop % sed '


s/test/trial/g


'ddd


this 


isa trial of the trial script.


this 


isthe second trial of the trial script.


macname@localhost desktop %

p替換標記會列印與替換命令中指定的模式匹配的行。這通常會和sed的-n選項一起使用。

-n選項將禁止sed編輯器輸出。但p替換標記會輸出修改過的行。將二者配合使用的效果就是 只輸出被替換命令修改過的行

macname@localhost desktop %cat ddd


this 


isa test of the test script.


this 


isthe second test of the test script.


dededede


hahahahhahahaah


macname@localhost desktop %macname@localhost desktop % sed -n '


s/test/trial/p


'ddd


this 


isa trial of the test script.


this 


isthe second trial of the test script.


macname@localhost desktop %

w替換標記會產生同樣的輸出，不過會將輸出儲存到指定檔案中

macname@localhost desktop %cat ddd


this 


isa test of the test script.


this 


isthe second test of the test script.


dededede


hahahahhahahaah


macname@localhost desktop % sed '


s/test/trial/w test.txt


'ddd


this 


isa trial of the test script.


this 


isthe second trial of the test script.


dededede


hahahahhahahaah


macname@localhost desktop %cat test.txt


this 


isa trial of the test script.


this 


isthe second trial of the test script.


macname@localhost desktop %

sed編輯器允許選擇其他字元來作為替換命令中的字串分隔符,這裡感嘆號被用作字串分隔符

macname@localhost desktop %cat ddd


this 


isa test of the test script.


this 


isthe second test of the test script.


dededede


hahahahhahahaah


macname@localhost desktop %macname@localhost desktop % sed -n '


s!test!trial!p


'ddd


this 


isa trial of the test script.


this 


isthe second trial of the test script.


macname@localhost desktop %

在這個例子中，感嘆號被用作字串分隔符，這樣路徑名就更容易閱讀和理解了。

macname@localhost desktop %macname@localhost desktop % sed '


s!/bin/bash!/bin/csh!


' /etc/passwd

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