Combine multiple unix commands into one output

Question

I need to search our mail logs for a specific e-mail address. We keep a current file named maillog as well as a week's worth of .bz2 files in the same folder. Currently, I'm running the following commands to search for the file:

grep person@domain.com maillog
bzgrep person@domain.com *.bz2

Is there a way combine the grep and bzgrep commands into a single output? That way, I could pipe the combined results to a single e-mail or a single file.

Answer 1

Another way is

{grep ...; bzgrep ...} >file

&& has the difficulty that the bzgrep wouldn't be run if the grep failed.

Answer 2

bzgrep automatically defaults to regular grep if a file isn't bzip-compressed. Thus the following should be sufficient:

bzgrep person@domain.com maillog *bz2 | mail -s "logs yay" someuser@blah

oh also of course here's my obligatory GNU Parallel solution too:

parallel -m bzgrep person@domain.com ::: maillog* *bz2 | mail -s "logs yay" someuser@blah

which could be a lot faster if you are checking a lot of files.

Answer 3

Here's another way to do it (assuming you're running bash, which you probably are):

cat <(bzgrep ...) <(grep ...)

Here bash is transparently feeding the output of the bzgrep and grep commands into cat as if they were files (and they sort of are under the hood, details in url at the bottom).

In your particular case I'd recommend Phil's solution, but the above is a good trick to keep in your bag.

If you're interested, you can read more here: http://www.tldp.org/LDP/abs/html/process-sub.html

Answer 4

You can tie the commands together with && which will allow you to run each command.

you could also add >> textfile.txt to the end of each command and have the output hit a file then mail that file out.