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UGU: Unix Guru Universe - Unix Tip #4350- February  7, 2025
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 Unix Tip #4350- February  7, 2025
 
THE BAD AND THE GOOD  
  
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.  
  
  
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
 4349
 - SUSPEND A VI SESSION FOR SHELL
 4348
 - BC AND NOT BEFORE AD
 4347
 - LISTING FILES BY SIZE
 4346
 - WHERE AM I ALWAYS
 4345
 - WHO SENT ME MAIL
 
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