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UGU: Unix Guru Universe - Unix Tip #4480- June 17, 2025
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 Unix Tip #4480- June 17, 2025
 
EFFICIENT COMMANDS  
  
I cringe anytime I see someone code  
inefficiently.  Here are three of the  
most common mistakes, followed by a  
better way to do the same thing.  
  
Bad:    cat somefile | grep something  
Better: grep something somefile  
Why:    You're running one program (grep) instead of two (cat and grep).  
  
Bad:    ps -ef | grep something | grep -v grep  
Better: ps -ef | grep [s]omething  
Why:    You're running two commands (grep) instead of three (ps  
and two greps).  
  
Bad:    cat /dev/null > somefile  
Better: > somefile  
Why:    You're running a command (cat) with I/O redirection,  
instead of just redirection.  
  
Although the bad way will have the  
same result, the good way is far  
faster.  This may seem trivial, but  
the benefits will really show when  
dealing with large files or loops.  
  
Regards.  
  
This tip generously supported by: sec@nbnet.nb.ca  
 NOTE: All tips provided are USE AT YOUR OWN RISK. Tips are submitted
by various unix admins around the globe. UGU suggest you read and
test each tip in a non-volitile environment before placing into
production.
  
LAST 5 TIPS
 4479
 - TOO MANY FILES AROUND
 4478
 - EXTRACT RELATIVE FROM ABSOLUTE
 4477
 - BELIEVE THE VENDOR?
 4476
 - REMOVING CORES CONDITIONALLY
 4475
 - INSERTING LINES WITHIN SCRIPTS
 
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