CODEWITHSUNDEEP
shellunixscriptingsedawk
user1831356
user1831356

Reputation: 11

shell scripts how to replace string between 2 characters in all lines start with specific string?

I have a text file like below, I want to replace the old string between 2 characters(in this case is ^ and |) with new string (in this case will be replaced to old string ^ old string)if the line start with specific string (in this example is MMX.

text file original:

General start, this is a test file.
TAG okay, this line not need to be processed.
MMX ABCD ^string1|other strings abc
CCF ABCD ^string2|other strings cde, skip line
MMX CDEE ^String3|other strings aaa
MMX AAAA ^String4|other strings bbb
CCD BBBB ^String5|other strings ccc, skip line

text file after modify should be:

General start, this is a test file.
TAG okay, this line not need to be processed.
MMX ABCD ^string1^String1|other strings abc
CCF ABCD ^string2|other strings cde, skip line
MMX CDEE ^String3^String3|other strings aaa
MMX AAAA ^String4^String4|other strings bbb
CCD BBBB ^String5|other strings ccc, skip line

How can I use shell scripts to perform this job?

Upvotes: 1

Views: 1731

Answers (6)

Ed Morton
Ed Morton

Reputation: 203189

Just for completeness:

$ awk '/^MMX/{sub(/\^[^|]+/,"&&")}1' file
General start, this is a test file.
TAG okay, this line not need to be processed.
MMX ABCD ^string1^string1|other strings abc
CCF ABCD ^string2|other strings cde, skip line
MMX CDEE ^String3^String3|other strings aaa
MMX AAAA ^String4^String4|other strings bbb
CCD BBBB ^String5|other strings ccc, skip line

but I'd use one of the posted sed solutions since this is a simple substitution on a single line which is what sed is good at.

Upvotes: 1

glenn jackman
glenn jackman

Reputation: 246744

To ensure capitalization in the new string:

sed '/^MMX/s/\^\([^|]\+\)/^\1^\u\1/'

Upvotes: 0

Vijay
Vijay

Reputation: 67211

perl -plne "if(/^MMX/){$_=~s/([^\^]*)([^\|]*)(.*)/$1$2$2$3/g;}" your_file

tested below:

>perl -plne "if(/^MMX/){$_=~s/([^\^]*)([^\|]*)(.*)/$1$2$2$3/g;}" new.txt
General start, this is a test file.
TAG okay, this line not need to be processed.
MMX ABCD ^string1^string1|other strings abc
CCF ABCD ^string2|other strings cde, skip line
MMX CDEE ^String3^String3|other strings aaa
MMX AAAA ^String4^String4|other strings bbb
CCD BBBB ^String5|other strings ccc, skip line

Upvotes: 0

user123444555621
user123444555621

Reputation: 152956

You can provide sed with an "address", which is a filter for the lines that the command is executed on:

sed '/^MMX/s/\^(.*)\|/^\1^\1|/g'

in this case, the address is /^MMX/, the command is s///g, and it replaces \^(.*)\| with ^\1^\1|, where \1 is the part in parentheses.

Upvotes: 0

Steve
Steve

Reputation: 54392

Here's one way using sed:

sed '/^MMX/s/\(\^[^|]*\)/\1\1/' file.txt

Results:

General start, this is a test file.
TAG okay, this line not need to be processed.
MMX ABCD ^string1^string1|other strings abc
CCF ABCD ^string2|other strings cde, skip line
MMX CDEE ^String3^String3|other strings aaa
MMX AAAA ^String4^String4|other strings bbb
CCD BBBB ^String5|other strings ccc, skip line

Upvotes: 3

Vishal Kumar
Vishal Kumar

Reputation: 802

sed s/^MMX([^^])^([^|])\|(.+)/MMX\1^\2^\2\|\3/ fileName

Upvotes: -2

Related Questions