Correct searching for rpm in PATH

[hadogenes]

Signed-off-by: Jacek Szafarkiewicz szafar@linux.pl

[evelikov]

The commit message is very misleading - the searching is the same, the output redirection is changed.
Something like "dkms: redirect stderr to null during rpm detection" would be a better name. @hadogenes can you please re-spin?

[xuzhen]

The elif [ `which rpm 2>/dev/null` ]; then just checks if rpm file exists. We can use elif which rpm &>/dev/null; then or elif command -v rpm &>/dev/null; then instead

[hadogenes]

The commit message is very misleading - the searching is the same, the output redirection is changed. Something like "dkms: redirect stderr to null during rpm detection" would be a better name. @hadogenes can you please re-spin?

But [ `which rpm >/dev/null` ] is always false ([ ] test is checking if string is not empty and when we add > /dev/null, then test is always false)

$ which true                                                                                                                                                                                   
/usr/bin/true
$ [ `which true > /dev/null` ] && echo ok || echo fail
fail
$ [ `which true 2> /dev/null` ] && echo ok || echo fail
ok
[ `which not_exists 2> /dev/null` ] && echo ok || echo fail 
fail

[evelikov]

@hadogenes sorry for misleading you there - you're right this fixes the check, but as a whole the existing code is subpar. Can you please follow xuzhen's advice - thanks in advance.

[evelikov]

Fixed up myself, thanks for the great suggestion xuzhen.