dmesg命令将其管道传输到grep

Question

I am running dmesg that contains info about devices and drives connected to the computer. the IDE drive shows up as "hd" followed by a letter starting at "a". I need to use the grep command to find things that contain hd or sd followed by a letter.

I know it's something along the lines of this:

dmesg | grep ... but I'm having trouble writing the regex for it. How do I do that?

Answer 1

Try grep '[hs]d[az]'

So, dmesg | grep '[hs]d[az]' dmesg | grep '[hs]d[az]'

EDIT

As mentioned below, you can do LC_ALL=C ; dmesg | grep '[hs]d[az]' LC_ALL=C ; dmesg | grep '[hs]d[az]' LC_ALL=C ; dmesg | grep '[hs]d[az]' to make sure that your locale does not do wonky stuff with the [az] .

END EDIT

If you want to match only things that begin with that, use '^[hs]...'

The ^ matches the beginning of the line, so it would match:

hda1 is something

and it would not match

i found hda1 here...

Answer 2

The answer by @mikeb is good, he just has a spurious | character in his character class [h|s] which is a mistake.

If you want to make sure that the string only consists of hda, hdb, hdc, sda, sdb, sdc etc with no other letters before of after that you can use "\\b" to match word boundaries.

dmesg | grep '\b[hs]d[a-z]\b'

If you want to know about partitions, remove the \\b at the end and replace it with \\d (for digits):

dmesg | grep '\b[hs]d[a-z]\d'

or just leave it out then it will match both drives and partitions:

dmesg | grep '\b[hs]d[a-z]'