PCRE regex to sed regex

Question

First of all sorry for my bad english. I'm a german guy.

The code given below is working fine in PHP:

$string = preg_replace('/href="(.*?)(\.|\,)"/i','href="$1"',$string);

Now T need the same for sed. I thought it should be:

sed 's/href="(.*?)(\.|\,)"/href="{$\1}"/g' test.htm

But that gives me this error:

sed: -e expression #1, char 36: invalid reference \1 on `s' command's RHS

Answer 1

You need a backslash in front of the parentheses you want to reference, thus

sed 's/href="\(.*?\)(.|\,)"/href="{$\1}"/g' test.htm

Answer 2

You have to escape the block selector characters ( and ) as follows.

sed 's/href="\(.*?\)\(.|\,\)"/href="{$\1}"/g' test.htm

Answer 3

sed does not support non-greedy regex match.

Answer 4

If you want to match a literal ".", you need to escape it or use it in a character class. As an alternative to slashing the capturing parentheses (which you need to do with basic REs), you can use the -E option to tell sed to use extended REs. Lastly, the REs used by sed use \N to refer to subpatterns, where N is a digit.

sed -E "s/href=([\"'])([^\"']*)[.,]\1/href=\1\2\1/i"

This has its own issue that will prevent matches of href attributes that use both types of quotes.

man sed and man re_format will give more information on REs as used in sed.

Answer 5

sed -e 's|href=\"\(.[^"][^>]*\)\([.,]\)\">|href="\1">|g' file

Answer 6

here is a solution, it is not prefect, only deal with the situation of one extra "," or "."

sed -r -e 's/href="([^"]*)([.,]+)"/href="\1"/g' test.htm