unix tr find and replace

unix sed awk tr
Kamran224 picture Kamran224 · Dec 2, 2011 · Viewed 45.1k times · Source

This is the command I'm using on a standard web page I wget from a web site.

tr '<' '\n<' < index.html

however it giving me newlines, but not adding the left broket in again. e.g.

 echo "<hello><world>" | tr '<' '\n<'

returns 

 (blank line which is fine)
 hello>
 world>

instead of 

 (blank line or not)
 <hello>
 <world>

What's wrong?

Answer

ephemient picture ephemient · Dec 2, 2011

That's because tr only does character-for-character substitution (or deletion).

Try sed instead.

echo '<hello><world>' | sed -e 's/</\n&/g'

Or awk.

echo '<hello><world>' | awk '{gsub(/</,"\n<",$0)}1'

Or perl.

echo '<hello><world>' | perl -pe 's/</\n</g'

Or ruby.

echo '<hello><world>' | ruby -pe '$_.gsub!(/</,"\n<")'

Or python.

echo '<hello><world>' \
| python -c 'for l in __import__("fileinput").input():print l.replace("<","\n<")'

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