delete lines with sed match a special regex

Question

I try to delete all lines that begin with some optional special chars followed by blubb:

That's the lines I want to match:

#blubb
*blubb
-blubb
blubb

That should do it, but doesn't work :(

sed "/^.?blubb$/d" -i special.conf  
sed "/^[#*-]?blubb$/d" -i special.conf

Has somebody the right solution?

anubhava · Accepted Answer · 2012-05-30T19:34:23.843

45

Use this sed command:

sed -i.old '/^[#*-]\{0,1\}blubb/d' special.conf

OR

sed -i.old -E '/^[#*-]?blubb/d' special.conf

OR

sed -i.old -r '/^[#*-]?blubb/d' special.conf

edited May 30 '12 at 19:34

answered May 30 '12 at 19:28

anubhava

Ah yes `\?` and `\+` are GNU extensions. – potong May 30 '12 at 19:59
I don't see how they would work even with GNU sed. Once they are escaped with back-slash, they lose their special meaning (and they have those special meanings only when `-r` is specified). – Happy Green Kid Naps May 30 '12 at 22:40
2

Hello, this works perfectly for me too. But I don't understand what the option -i.old and -E or -r does. Thanks – David Okwii May 13 '16 at 09:44
8

-i is for inline editing and -r or -E is for extended regex in sed – anubhava May 13 '16 at 20:03
1

can u please explain what is the '.old' suffix ? – chenchuk Jun 21 '18 at 05:50
5

@chenchuk: That is used as extension for creating backup copy for inline editing. – anubhava Jun 21 '18 at 07:47

1 Answers1