Hard-Luck Editing the /etc/inittab File in Maintenance Mode

Problem(Abstract) This technote describes a technique for creating a minimal /etc/inittab file if no other tools are available.

Cause

A bad entry in the /etc/inittab is keeping the system from booting properly.

Resolving the problem

Ordinarily if there is a problem with one or more entries in the /etc/inittab the preferred method of editing it is: 1. Boot into Maintenance Mode off AIX install CDs, mksysb, or NIM 2. Access the rootvg and start a shell with the filesystems mounted. 3. Edit /etc/inittab down to a minimum 3 lines: init:2:initdefault: brc::sysinit:/sbin/rc.boot 3 >/dev/console 2>&1 # Phase 3 of system boot cons:0123456789:respawn:/usr/sbin/getty /dev/console In cases where the rootvg filesystems cannot be mounted automatically (for example the CD media is a different Technology Level than what exists on hard disk; or the filesystems for some reason won't automatically mount), commands such as the "vi" editor won't be available to edit the inittab. In this case a hard-luck method can be used to create a minimal inittab. 1. Boot into Maintenance Mode and choose Option 2 "Access rootvg and start a shell before mounting filesystems". 2. Once in Maintenance Mode, fsck all rootvg filesystems necessary: # fsck /dev/hd1 # fsck /dev/hd2 # fsck /dev/hd3 # fsck /dev/hd4 # fsck /dev/hd9var 3. Mount root on a temporary mount point: # mount /dev/hd4 /mnt 4. Copy the bad inittab to a backup: # cd /mnt/etc # mv inittab inittab.bad 5. Use grep to create a minimal new inittab: # grep "init:" inittab.bad > inittab (adds both the init: and brc: entries) # grep "^cons:" inittab.bad >> inittab (adds the cons: entry) 6. Reboot using the new inittab: # sync; sync; sync # cd / # umount /mnt power cycle the system from the front panel or HMC