postfix.sh: add missing -E for extended regexes in smtpd_sender_restrictions

[ap-wtioit]

Description

Noticed that something was wrong when in our tests i got the following additional output:

sed: -e expression #1, char 111: invalid reference \1 on `s' command's RHS

Type of change

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation (README.md or the documentation under docs/)
• If necessary I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

Info @wt-io-it

[georglauterbach]

Well, sed is one crude tool.. I thought -E is only necessary when using more sophisticated regular expressions. Oh my..

[ap-wtioit]

For unescaped brackets you have to use -E in sed and grep:

echo "abc" | sed 's/\(b\)/d/'
echo "abc" | sed -E 's/(b)/d/'

I think both grep and sed use POSIX basic regular expressions as default and we are not used to those any more.

[georglauterbach]

That explains the weirdness of the "old code" in #3271 - thanks for the info :)

[casperklein]

sed --> sedfile to get notified in the future, if no change takes place.