init – the parent of any linux process
The first application executed by linux after booting is “init”, normally it’s located at /sbin/init, but if not available then kernel linux will try to find /etc/init or /bin/sh if /etc/init not found/corrupted.
you can try execute “pstree” on your linux console:
$ pstree -G
init─┬─bdflush
├─crond
├─httpd───12*[httpd]
├─keventd
├─khubd
├─6*[kjournald]
├─klogd
├─kscand/DMA
├─kscand/HighMem
├─kscand/Normal
├─ksoftirqd_CPU0
├─ksoftirqd_CPU1
├─kswapd
├─kupdated
├─login───bash
├─mdrecoveryd
├─5*[mingetty]
├─mysqld_safe───mysqld-max
├─named
├─scsi_eh_0
├─scsi_eh_1
├─squid───squid─┬─5*[ncsa_auth]
│ └─unlinkd
├─sshd─┬─sshd───sshd───bash───su───bash───su───bash───ps+
│ └─sshd───sshd
├─syslogd
└─vsftpd
pstree will print tree structure of any running process on your Linux. You see that init is obviously the parent of everything. So, what “init” does?
init will read /etc/inittab and follow any instruction inside this file. For details please read manual init and inittab
