5.2.3. /proc/cmdline
This file shows the parameters passed to the kernel at the time it is started. A sample
/proc/cmdline file looks like the following:
ro root=/dev/VolGroup00/LogVol00 rhgb quiet 3
This output tells us the following:
- ro
- The root device is mounted read-only at boot time. The presence of
roon the kernel boot line overrides any instances ofrw. - root=/dev/VolGroup00/LogVol00
- This tells us on which disk device or, in this case, on which logical volume, the root filesystem image is located. With our sample
/proc/cmdlineoutput, the root filesystem image is located on the first logical volume (LogVol00) of the first LVM volume group (VolGroup00). On a system not using Logical Volume Management, the root file system might be located on/dev/sda1or/dev/sda2, meaning on either the first or second partition of the first SCSI or SATA disk drive, depending on whether we have a separate (preceding) boot or swap partition on that drive.For more information on LVM used in Red Hat Enterprise Linux, refer to http://www.tldp.org/HOWTO/LVM-HOWTO/index.html. - rhgb
- A short lowercase acronym that stands for Red Hat Graphical Boot, providing "rhgb" on the kernel command line signals that graphical booting is supported, assuming that
/etc/inittabshows that the default runlevel is set to 5 with a line like this:id:5:initdefault:
- quiet
- Indicates that all verbose kernel messages except those which are extremely serious should be suppressed at boot time.
