While reading through crontab(5) this morning I came across this useful nugget of information:
“These special time specification “nicknames” are supported, which replace the 5 initial time and date fields, and are prefixed by the @ character:
@reboot : Run once, at startup.
@yearly : Run once a year, ie. “0 0 1 1 *”.
@annually : Run once a year, ie. “0 0 1 1 *”.
@monthly : Run once a month, ie. “0 0 1 * *”.
@weekly : Run once a week, ie. “0 0 * * 0”.
@daily : Run once a day, ie. “0 0 * * *”.
@hourly : Run once an hour, ie. “0 * * * *”.”
So instead of writing:
0 * * * * command
You can specify hourly to accomplish the same thing:
Or if you want to run something when a machine is rebooted you can add this:
@reboot echo “” | mail -s “`/bin/hostname` was recently rebooted” root
Several of these short cuts are rather handy and it makes things easier to read IMHO. Gotta love short cuts!
I recently got the opportunity to start supporting a number of AIX systems, and being an AIX newbie the first thing I did was ask myself how can I learn everything there is to know about AIX (more to come on this topic tomorrow)? Being a readaholic, I decided to wander over to Amazon to see which AIX books were available.
After 10 minutes of searching and reading reviews, I ended up snagging a copy of AIX 5L Administration for $5. That $5 also included shipping! This led me to start looking at the “used” link associated with various other books I really wanted, and the used prices were typically at least 50% off the price Amazon lists for a new book (the book I got was unused, which is new to me!). This may be old news to everyone else, but I like the fact that I can now expand my technical library on the cheap! Thought I would pass this on to my fellow geeks.
I built out a Solaris 10 update 10 guest on a vSphere 4.1 machine this past week. When I went to configure VMWare tools I received the following error:
Stopping VMware Tools services in the virtual machine:
Guest operating system daemon: done
Guest memory manager: done
Unable to create symlink "/mnt/hgfs" pointing to file "/hgfs".
After doing some debugging I noticed that /mnt is used temporarily and if you happen to be using it (or if volfs is) the installer will fail. I temporarily stopped volfs and unmounted a device that was mounted on /mnt and the installer completed without issue. Figure I would share this with others so you don’t have to waste your time debugging this problem.