Welcome to the Linux Foundation Forum!

Will Printk() output to the standard terminal?

cheesysam
cheesysam Posts: 4
in Kernel Development

I've put some printk()'s in some of the filesystem files of the linux source tree to try and trace what's going on.

When I run dmesg, I can see a few of my traces, however they aren't showing as I would have expected when I then call the functions again via the terminal.

How can I call some of the system calls and see a modified output?

Comments

  • cheesysam
    cheesysam Posts: 4
    Just gonna answer my own question in-case anyone else is looking for it.

    printk() at the default level, outputs to the /var/log/messages file
    printk("I am at default level");

    The printk level can be defined however to the following levels.
    KERN_EMERG
    KERN_ALERT
    KERN_CRIT
    KERN_ERR
    KERN_WARNING
    KERN_NOTICE
    KERN_INFO
    KERN_DEBUG
    printk(KERN_CRIT "I am a critical level printk");

    If it's critical or above, it will print in the terminal as well as /var/log/messages

Categories

Upcoming Training