CODEWITHSUNDEEP
regexsed
uutsav
uutsav

Reputation: 409

sed not working for special characters

I am trying to replace text using sed at word boundaries. After looking at Beginning and end of words in sed and grep, I use:

echo "It is a @ at a@ ." | sed "s/\ba\b/#/g"

Output: It is # @ at a@ .

which works perfectly, but when I try to replace words which begin or end in special characters like @, it does not work.

echo "It is a @ at a@ ." | sed "s/\b@\b/#/g"

Output: It is a @ at a@ .

echo "It is a @ at a@ ." | sed "s/\ba@\b/#/g"

Output: It is a @ at a@ .

I am missing something ? How can I replace whole words that end in special characters using sed ?

Upvotes: 0

Views: 1623

Answers (1)

Avinash Raj
Avinash Raj

Reputation: 174696

You need to use \B

$ echo "It is a @ at a@ ." | sed "s/\B@\B/#/g"
It is a # at a@ .

\b - matches between a word char and non-word char (vice-versa)

\B - matches between two word chars or two non-word chars.

So the char exists before @ is space which is a non-word character. So to match the boundary which exists between two non-word chars, you need to use \B and the character exists after @ is also the space character. So here, you need to use \B also.

For the second case, you have to use this,

$ echo "It is a @ at a@ ." | sed "s/\ba@\B/#/g"
It is a @ at # .

Demo

Upvotes: 2

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