doubt regardin regex in grep - Shell Programming and Scripting

evergreen_cool · #1 09-11-2005

shudnt this command :
grep [^C] test

give all the lines which do not hv 'C'. ^ wrks as negating character inside square brackets right ???

bt in my case grep is printin all the line in the file

also wht does
grep c+ test & grep c? test
shud do ???

blowtorch · #2 09-11-2005

Well, I dont know what exactly [^C] will do, but just ^C matches all lines that start with an upper case 'C'.

Ygor · #3 09-11-2005

Looks like a homework assignment.

bwreed · #4 09-02-2008

I know this is an old question, but here's an old answer to match. (It's old because I'm sure the grep command hasn't changed).
[^C] matches any character that's NOT a C.
You might want
$ grep -E "^[^C]*$" test
or more likely, you want
$ grep -vE "[C]" test

cfajohnson · #5 09-02-2008

Quote:

Originally Posted by bwreed

[^C] matches any character that's NOT a C.

And, since it is not quoted, it will expand to all the single-letter filenames in the current directory (other than C itself).

As a result, the search pattern will be the first matching file, and any others matching files will be searched along with 'test'.

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