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Is there an easy way to convert HTML special entities from a data stream? I'm passing data to a bash script and sometimes that data includes special entities. For example:

"test" & test $test ! test @ # $ % ^ & *

I'm not sure why some characters show up fine and other don't but unfortunately, I don't have control over the data coming in.

I'm thinking I might be able to use SED here but that seems like it would be cumbersome and possibly prone to false positives. Is there a Linux command I could pipe to that specializes in decoding this type of data?

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3 Answers 3

up vote 5 down vote accepted

PHP is well suited to this. This example requires PHP 5:

cat file.html | php -R 'echo html_entity_decode($argn);'
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Thanks for the great idea but for some reason I'm getting an error: PHP Warning: html_entity_decode() expects at least 1 parameter, 0 given in Command line run code on line 1 –  Mike B Oct 22 '12 at 4:30
Of course. Shell quoting strikes again. Try it with single quotes. –  Michael Hampton Oct 22 '12 at 13:19
Thanks. That resolved it. –  Mike B Oct 23 '12 at 16:51

Perl is (as always) your friend. I think this will do it:

perl -n -mHTML::Entities -e ' ; print HTML::Entities::decode_entities($_) ;'


echo '"test" & test $test ! test @ # $ % ^ & *' |perl -n -mHTML::Entities -e ' ; print HTML::Entities::decode_entities($_) ;'

With output:

someguy@somehost ~]$ echo '"test" & test $test ! test @ # $ % ^ & *' |perl -n -mHTML::Entities -e ' ; print HTML::Entities::decode_entities($_) ;'
"test" & test $test ! test @ # $ % ^ & *
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This works on my OSX10.8 laptop and a RHEL5.something host. –  Jason Tan Oct 22 '12 at 5:52
In order to output the file in UTF-8, use binmode: echo "«" | perl -n -mHTML::Entities -mutf8 -e 'binmode(STDOUT, ":utf8"); print HTML::Entities::decode_entities($_) ;' –  falstaff Nov 23 '13 at 22:46

Takes text file from stdin:

while read lin; do
  # ...other entites
  echo "$newl"

It probably needs bash >= version 4

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