What does rpm -qa |grep th* (as compared to rpm -qa |grep th) display?

davidas · 03-18-2004, 12:29 AM

rpm -qa |grep th displays packages with "th" in their name.

What do rpm -qa |grep th* and rpm -qa |grep *th display? I don't quite understand the output. rpm -qa |grep th* seems to display any package with "t" in the name?!

Some concept teaching required here

Thanks !

Demonbane · 03-18-2004, 12:43 AM

Grep takes regular expressions, so "grep th*" is actually equivalent to "any line that has the letter 't' and any number of 'h'(including 0)".
If you want to grep for packages that start with "th", try

Code:

rpm -qa | grep ^th

davidas · 03-18-2004, 01:35 AM

Could you elaborate on "regular expressions"? Does "grep th3" refers to "any line that has the letter 't' and 3 instances of 'h'"?

Thanks !

Quote:

Originally posted by Demonbane
Grep takes regular expressions, so "grep th*" is actually equivalent to "any line that has the letter 't' and any number of 'h'(including 0)".
If you want to grep for packages that start with "th", try

Code:

rpm -qa | grep ^th