grep multipe wildcards in string - linux

Question

Say I have a file that contains:
Release 2.1 OS: RHEL File: package_el6_2.0.1.1_x86_64.rpm
Release 2.1 OS: RHEL File: package_el6_2.0.1.1_i686.rpm
Release 2.1 OS: RHEL File: package_el7_2.0.1.1_x86_64.rpm
Release 2.1 OS: RHEL File: package_el7_2.0.1.1_i686.rpm
I want to grep and match lines that only contain 'package', 'el6', and 'x86_64'
How would I go about doing that on a one liner using grep? The line must match all three and grep shouldn't care about how many characters are in between. If there is a better tool for the job, I'm happy to use that instead.
I've tried the following and got no results:
grep package*el6*x86_64*
Seeing posts and documentation, I understand that * does not mean the same thing as it would in shell. I'm looking for the equivalent of it to use in regex. Hope this makes sense.

Answer 1

Your attempt is very close. * in shell glob terms is roughly equivalent to .* in regex terms. . means "any character" and * is means "repeated any number of times (including zero).
Your regex just needs . before each *. The trailing * is not necessary:
package.*el6.*x86_64
Here is a sample run with your input:
grep 'package.*el6.*x86_64' <<< "Release 2.1 OS: RHEL File: package_el6_2.0.1.1_x86_64.rpm
Release 2.1 OS: RHEL File: package_el6_2.0.1.1_i686.rpm
Release 2.1 OS: RHEL File: package_el7_2.0.1.1_x86_64.rpm
Release 2.1 OS: RHEL File: package_el7_2.0.1.1_i686.rpm"
Prints:
Release 2.1 OS: RHEL File: package_el6_2.0.1.1_x86_64.rpm

Answer 2

Not the best solution (in fact ineficient), but really easy to remember: join 3 greps
grep "package" | grep "el6" | grep "x86_64"

Answer 3

If they're guarenteed to be in order, then a simple grep:
grep "package.*el6.*x86_64" file.txt
would do it. If the items can be in any order, you can try a pipe:
cat file.txt | grep package | grep el6 | grep x86_64
will only show lines containing all three, but in any order

Answer 4

You can use egrep
egrep 'package|el6|x86_64' name_of_file.txt