sed replace a newline and a literal with literal?

Question

Im trying to replace this text with this command but it doesn't work:

sed -e 's/\nnumber2/number2/g'  fffff > fffff

This is what my file contains:

number1;gAMMA
number2;gat
number1;zilla
number2;dog

This is my expected output:

number1;gAMMAnumber2;gat
number1;zillanumber2;dog

The problems are: (1) Do not read and redirect to the same file. You have to write to another file to be safe. (2) `sed` only reads one line at a time, so you cannot replace newlines. [There is a hack](http://unix.stackexchange.com/a/26290/187122) but I would recommend `perl` instead. (3) You may have to write `$'...\n...'` instead of `...\n...`. — Socowi, Mar 20 '17 at 18:19

score 1 · Answer 1 · answered Mar 20 '17 at 18:28

1

awk to the rescue!

$ awk '/^number2/ {n=1} 
       {printf "%s"(n?"\n":""), $0; n=0}' file > tmp && mv tmp file

or perhaps set ORS and use print

answered Mar 20 '17 at 18:28

karakfa

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score 1 · Accepted Answer · edited May 23 '17 at 12:17

1

sed ':a;N;$!ba;s/\nnumber2/number2/g' fffff > fffff

here is the explanation

edited May 23 '17 at 12:17

Community

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answered Mar 20 '17 at 18:28

cur4so

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taskalman · Answer 3 · 2017-03-20T18:36:47.990

1

As mentioned in the comments already, Perl would probably be better suited for this multiline task:

perl -i.bak -pe 's/(number1[^\n]*)\n/\1/' yourfile.txt

There is probably a more elegant way to do this with Perl, but this is fairly straight forward. It will also create a backup file with .bak extension, if you don't want that, omit the bak part.

edited Mar 20 '17 at 18:36

answered Mar 20 '17 at 18:29

taskalman

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sed replace a newline and a literal with literal?

3 Answers3