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UGU: Unix Guru Universe - Unix Tip #4516- July 22, 2024 - Home : Help : Today's Tip
Unix Tip #4516- July 22, 2024

ACCIDENTS WITH CRONTAB

ACCIDENTS WITH CRONTAB



Ever typed the crontab
Ever typed the crontab
command and forgot
command and forgot
the -l option?
the -l option?


That's kinda dangerous,
That's kinda dangerous,
for if you hit ctrl-D
for if you hit ctrl-D
to get back to the
to get back to the
prompt, your crontab's
prompt, your crontab's
gone.
gone.


To prevent this, make a
To prevent this, make a
script with the following
script with the following
contents:
contents:


#!/bin/ksh
#!/bin/ksh
if [[ $# -eq 0 ]] ; then
if [[ $# -eq 0 ]] ; then
echo "crontab: no option specified. Aborted."
echo "crontab: no option specified. Aborted."
exit 2
exit 2
else
else
/usr/bin/crontab "$@"
/usr/bin/crontab "$@"
fi
fi




Make sure the script is
Make sure the script is
executable and put it in
executable and put it in
a directory that's in your
a directory that's in your
PATH BEFORE the /usr/bin
PATH BEFORE the /usr/bin
directory.
directory.


Now if you type crontab
Now if you type crontab
without option or filename,
without option or filename,
you'll just get an error
you'll just get an error
message. If you want to pipe
message. If you want to pipe
some stuff to crontab, you
some stuff to crontab, you
still can do it like this:
still can do it like this:


% somecommand | crontab -
% somecommand | crontab -




This tip generously supported by: kees.couprie+ugu@swift.com
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.


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
LAST 5 TIPS
4515 - ROTATE THE ALPHABET
4515 - ROTATE THE ALPHABET
4514 - RECREATING DIRECTORY TREES
4514 - RECREATING DIRECTORY TREES
4513 - DID IT REBOOT?
4513 - DID IT REBOOT?
4512 - TERMINAL RESET
4512 - TERMINAL RESET
4511 - RENICE CPU HOGS

4511 - RENICE CPU HOGS


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