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UGU: Unix Guru Universe - Unix Tip #4088- April 21, 2012
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 Unix Tip #4088- April 21, 2012
 
ACCIDENTS WITH CRONTAB  
  
Ever typed the crontab  
command and forgot  
the -l option?  
  
That's kinda dangerous,  
for if you hit ctrl-D  
to get back to the  
prompt, your crontab's  
gone.  
  
To prevent this, make a  
script with the following  
contents:  
  
#!/bin/ksh  
if [[ $# -eq 0 ]] ; then  
echo "crontab: no option specified. Aborted."  
exit 2  
else  
/usr/bin/crontab "$@"  
fi  
  
  
Make sure the script is  
executable and put it in  
a directory that's in your  
PATH BEFORE the /usr/bin  
directory.  
  
Now if you type crontab  
without option or filename,  
you'll just get an error  
message. If you want to pipe  
some stuff to crontab, you  
still can do it like this:  
  
% somecommand | crontab -  
  
  
This tip generously supported by: kees.couprie+ugu@swift.com  
 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
 4087
 - ROTATE THE ALPHABET
 4086
 - RECREATING DIRECTORY TREES
 4085
 - DID IT REBOOT?
 4084
 - TERMINAL RESET
 4083
 - RENICE CPU HOGS
 
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