[Novalug] bash & grep question - best for optimizing?

[Ross Patterson]

At 09:08 11/13/2006, Nick Danger wrote:
>2. Should I do one grep for each pattern, or a single grep with multiple
>matches?

Assuming a modern grep,

         grep -rl -E "(pattern1)|(pattern2)|(pattern3)|(pattern4)" .

is likely to be the highest performance and most reliable.  In 
particular, assuming your hash-structured directory is kind of broad, 
grepping recursively on "." instead of on "*" will prevent the shell 
from trying to expand "*" into a list of subdirectory names.  There 
is a limit on the size of a command string, and this will avoid it 
and also cut down on the storage size to launch the command.

Ross