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Regex foo - checking crashkernel value

I need to check the crashkernel setting on all of my hosts.

The issue(s):
  • crashkernel=<blah> can exist anywhere in the string 
  • there may be several iterations of a boot entry which contains crashkernel
In this example, I purposely used a grub.conf which had 2 different crashkernel values to demonstrate how to change the enumeration of the test (either 1 or 2).

[root@rhvsrv01 ~]# egrep '^[[:space:]]*kernel /vmlinuz.*crashkernel=' /boot/grub/grub.conf | sed -r '1!d;s/.*crashkernel=([[:graph:]]+).*/\1/'
auto
 
[root@rhvsrv01 ~]# egrep '^[[:space:]]*kernel /vmlinuz.*crashkernel=' /boot/grub/grub.conf | sed -r '2!d;s/.*crashkernel=([[:graph:]]+).*/\1/'
16M@128M

[root@rhvsrv01 ~]# grep vmlinuz /boot/grub/grub.conf | grep -v \#
    kernel /vmlinuz-2.6.32-358.2.1.el6.x86_64 ro root=/dev/mapper/VolGroup00-LogVol01 rd_NO_LUKS LANG=en_US.UTF-8 rd_NO_MD SYSFONT=latarcyrheb-sun16 crashkernel=auto rd_LVM_LV=VolGroup00/LogVol01 rd_LVM_LV=VolGroup00/LogVol00  KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rhgb quiet elevator=deadline processor.max_cstate=1
    kernel /vmlinuz-2.6.32-358.el6.x86_64 ro root=/dev/mapper/VolGroup00-LogVol01 rd_NO_LUKS LANG=en_US.UTF-8 rd_NO_MD SYSFONT=latarcyrheb-sun16 crashkernel=16M@128M rd_LVM_LV=VolGroup00/LogVol01 rd_LVM_LV=VolGroup00/LogVol00  KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rhgb quiet


If you need to append something to the line starting with "    kernel"
  sed -i -e '/^.kernel/ s/$/ transparent_hugepage=never/' /boot/grub/grub.conf
 
 
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