UNIX for Dummies Questions & Answers

Can anyone explain this (i.e. why the 2nd grep does not find anything)?:

Code:

-bash-3.00$ cat tmp.log
sftp> chdir /home/test-dir
sftp> mget thosefiles*.txt
File "/home/test-dir/thosefiles*.txt" not found.

-bash-3.00$ grep "s*.txt" tmp.log
sftp> mget thosefiles*.txt
File "/home/test-dir/thosefiles*.txt" not found.

-bash-3.00$ grep "es*.txt" tmp.log
-bash-3.00$

Thanks in advance.

Dave

Because you're not matching what you wanna match.
Use grep "s\*\.txt" or grep "es\*\.txt".
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Bye

Thanks, Lem. Yes, I was able to make it work by escaping the *. Just wondering in this particular case why the two greps do what they do.

Without escaping, the expression "s*.txt" matches a string that begins with zero or more s, goes on with another char no matter what (matched by the period), then goes on with txt. So it matches '.txt', and not 's*.txt', in your file. It would match also 'atxt' or 'btxt'.

Without escaping, the expression "es*.txt" matches a string that begins with an e, goes on with zero or more s, goes on with another char no matter what (matched by the period), then goes on with txt. So it cannot match anything that contains '*.'

If your grep has the -o option, you can easily see it yourself what strings are really matched by your grep expressions.
--
Bye

Thanks very much, Lem.