PCRE Regex to SED - regex

Question

I am trying to take PCRE regex and use it in SED, but I'm running into some issues. Please note that this question is representative of a bigger issue (how to convert PCRE regex to work with SED) so the question is not simply about the example below, but about how to use PCRE regex in SED regex as a whole.
This example is extracting an email address from a line, and replacing it with "[emailaddr]".
echo "My email is abc#example.com" | sed -e 's/[a-zA-Z0-9]+[#][a-zA-Z0-9]+[\.][A-Za-z]{2,4}/[emailaddr]/g'
I've tried the following replace regex:
([a-zA-Z0-9]+[#][a-zA-Z0-9]+[\.][A-Za-z]{2,4})
[a-zA-Z0-9]+[#][a-zA-Z0-9]+[\.][A-Za-z]{2,4}
([a-zA-Z0-9]+[#][a-zA-Z0-9]+[.][A-Za-z]{2,4})
[a-zA-Z0-9]+[#][a-zA-Z0-9]+[.][A-Za-z]{2,4}
I've tried changing the delimited of sed from s/find/replace/g to s|find|replace|g as outlined here (stack overflow: pcre regex to sed regex).
I am still not able to figure out how to use PCRE regex in SED, or how to convert PCRE regex to SED. Any help would be great.

Answer 1

Want PCRE (Perl Compatible Regular Expressions)? Why don't you use perl instead?
perl -pe 's/[a-zA-Z0-9]+[#][a-zA-Z0-9]+[\.][A-Za-z]{2,4}/[emailaddr]/g' \
<<< "My email is abc#example.com"
Output:
My email is [emailaddr]
Write output to a file with tee:
perl -pe 's/[a-zA-Z0-9]+[#][a-zA-Z0-9]+[\.][A-Za-z]{2,4}/[emailaddr]/g' \
<<< "My email is abc#example.com" | tee /path/to/file.txt > /dev/null

Answer 2

Use the -r flag enabling the use of extended regular expressions. ( -E instead of -r on OS X )
echo "My email is abc#example.com" | sed -r 's/[a-zA-Z0-9]+#[a-zA-Z0-9]+\.[A-Za-z]{2,4}/[emailaddr]/g'
Ideone Demo

Answer 3

GNU sed uses basic regular expressions or, with the -r flag, extended regular expressions.
Your regex as a POSIX basic regex (thanks mklement0):
[[:alnum:]]\{1,\}#[[:alnum:]]\{1,\}\.[[:alpha:]]\{2,4\}
Note that this expression will not match all email addresses (not by a long shot).

Answer 4

for multiline use the 0!
perl -0pe 's/search/replace/gms' file

Answer 5

Sometimes this might be helpful too as a work-around:
str=$(grep -Poh "pcre-pattern" file)
sed -i "s/$str/$something_else/" file
-o, --only-matching:
Print only the matched (non-empty) parts of a matching line, with each such part on a separate output line.