On Fri, Jan 03, 2014 at 01:56:33PM -0700, Pete Travis wrote: > On Jan 3, 2014 1:16 PM, "Suvayu Ali" <fatkasuvayu+linux@xxxxxxxxx> wrote: > > On Thu, Jan 02, 2014 at 09:07:29PM -0700, Pete Travis wrote: > > > > > > $ su -c 'crontab -l' > > > * * * * * echo "TEST TEST" > > > $ crontab -l > > > * * * * LARSHAPPY="no"; if [[ "$LARSHAPPY" == "no" ]]; then echo -e > > > "This isn't the same.\nNew Things are Different.\nSome people like the > > > old thing.";fi > > > > > > $ journalctl SYSLOG_IDENTIFIER=CROND -f #filtered for convenience > > > > How do you know which IDENTIFIER to use? I could guess it should be > > CROND if I were to look at the output of journalctl in this case; but is > > there any canonical way to find this out? Or is it just the unit file > > name? > > I picked that by looking at the messages and pairing up the identifier with > my messages. It's reasonable to assume this will be consistent for cron > jobs, so I didn't demonstrate that part. > > The syslog identifier is not the same as the unit file. `journalctl -u > crond ` gives only stdout of crond itself, not the jobs. iirc, applications > using the journal API can choose the syslog identifier for their messages, > and one is chosen for them if not. I don't know the details behind that > choice, but I would suspect it comes from the calling binary or service > somehow. Okay, I think I understand. And if I add Lars's suggestion about relying on completion, I think I can start doing some exploring on my own ;). Although some authoritative documentation on this would be really cool, specially to respond to queries on the mailing list. > > > say! Let's take a closer look at a message: > > > > > > MESSAGE=(pete) CMDOUT (New Things are Different.) [...chomp...chomp...chomp...] > > > _BOOT_ID=0557929cbde247928f945d8b53a6e067 > > > > How did you get this output; I'm confused. > > > > `journalctl -o verbose' gives the extra metadata. There are other output > formats, ie json, but this seemed most useful here. > > `journalctl --show-cursor` gives the cursor at the end of the query. This is an interesting output flag. I will play more with it. I guess this provides a nice interface if I want to parse journalctl output from my own scripts (bash, python, whatever). > I pulled all of that from `man journalctl` , /usr/share/doc/ , examining > the metadata provided by "-o verbose", and generous mashing of the tab > key. There is a section in the System Administrators Guide on the journal, > which I will probably update this weekend since the usage is newly fresh in > my mind. It won't be published for f20 immediately, but I can push a draft > if anyone is interested in reviewing. (Hint, readers, speak up, or I won't > do the extra work) I would love to read that, and if I can give comments. I usually like doign documentation work :). > > > > > > > $ journalctl SYSLOG_IDENTIFIER=CROND _AUDIT_SESSION=83 -b > > > --show-cursor|tail -1 > > > - -- cursor: > > > > s=04f24177eb10446c94ea389f0e5adb2f;i=49d85;b=0557929cbde247928f945d8b53a6e067;m=b529d73d;t=4ef0878266935;x=ade119e61f79d8c4 > > > > It is not clear to me what is meant by cursor here (I read > > journalctl(1)); moreover I could not find an option to journalctl called > > `--show-cursor'. > > > > Think of the cursor as a unique key for the entry in a journal - but as I > understand it, it references that point in the journal, not the specific > entry. I have not read the code, so it is easier to demonstrate usage than > explain the internals. In practice, a script or application tracking the > journal can stop and resume at a specific point with more granularity and > reliability than a timestamp, because timestamps may not be unique. Thank you, I'll play with this myself. Sounds interesting. > > If you don't mind could you share some of your journalctl understanding > > on another thread I started? > > > > <https://lists.fedoraproject.org/pipermail/users/2014-January/444479.html> > > > > Thanks a lot for your time. > > No problem. I'll dig up that thread and see if I can help. Thanks a lot! :) -- Suvayu Open source is the future. It sets us free. -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Fedora Code of Conduct: http://fedoraproject.org/code-of-conduct Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines Have a question? Ask away: http://ask.fedoraproject.org
