启动 RHEL/CentOS 内核时提供的选项和参数可以在文件 /proc/cmdline 中查看。

# cat /proc/cmdline 
ro root=/dev/mapper/vg_os-lv_os rd_NO_LUKS LANG=en_US.UTF-8 rd_NO_MD SYSFONT=latarcyrheb-sun16 crashkernel=131M@0M rd_LVM_LV=vg_os/lv_os  KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rhgb quiet

与默认启动参数比较

我们可以将 /etc/grub.conf 文件与 /proc/cmdline 文件进行比较，以查看在引导内核时是否使用了相同的选项。
/etc/cmdline 对于确定内核是否使用与 /etc/grun.conf 文件中定义的参数/参数不同的参数/参数启动非常有用

# cat /etc/grub.conf 
# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE:  You have a /boot partition.  This means that
#          all kernel and initrd paths are relative to /boot/, eg.
#          root (hd0,0)
#          kernel /vmlinuz-version ro root=/dev/mapper/vg_os-lv_os
#          initrd /initrd-[generic-]version.img
#boot=/dev/sda
default=0
timeout=5
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title Red Hat Enterprise Linux 6 (2.6.32-504.el6.x86_64)
	root (hd0,0)
	kernel /vmlinuz-2.6.32-504.el6.x86_64 ro root=/dev/mapper/vg_os-lv_os rd_NO_LUKS LANG=en_US.UTF-8 rd_NO_MD SYSFONT=latarcyrheb-sun16 crashkernel=auto rd_LVM_LV=vg_os/lv_os  KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rhgb quiet
	initrd /initramfs-2.6.32-504.el6.x86_64.img