CODEWITHSUNDEEP
shellunixsed
user3225466
user3225466

Reputation: 1

Replacing entire word/number in a line with SED with only partial match

Can someone please tell me how I can replace a entire string with only partial? For Example if the txt file contains:

The number of water molecues: h20=20e43

And I need it to say:

The number of water molecues: h20=10e54

What I have so far is sed 's/h20/h20=10e54/', which outputs:

The number of water molecues: h20=10e54=20e43

The problem is that the original value I want to replace is not always the same so I need it to search for the patter h20= only and replace the whole thing.

Upvotes: 0

Views: 2016

Answers (3)

glenn jackman
glenn jackman

Reputation: 246744

Try: s/\(h20=\)[[:alnum:]]*/\110e54/

matches "h20=" (and remembers the value) followed by some alphanumeric chars; replaces with the remembered value (\1) plus the literal string you want.

Also: perl -pe 's/h20=\K\w+/10e54/'

Upvotes: 1

Jotne
Jotne

Reputation: 41446

awk can also be used:

echo "The number of water molecues: h20=20e43" | awk '{sub(/h20=.*/,"h20=10e54")}1'
The number of water molecues: h20=10e54

Upvotes: 0

BMW
BMW

Reputation: 45223

following your own idea, here is the fix.

echo "The number of water molecues: h20=10e54" |sed 's/h20=.*/h20=10e54/'

Upvotes: 0

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