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                 |  | UGU: Unix Guru Universe - Unix Tip #4516- July 23, 2025
 -  Home : Help
 : Today's Tip Unix Tip #4516- July 23, 2025
 
 
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
 4515
 - ROTATE THE ALPHABET
 4514
 - RECREATING DIRECTORY TREES
 4513
 - DID IT REBOOT?
 4512
 - TERMINAL RESET
 4511
 - RENICE CPU HOGS
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