Yes. It's safe to view any system file(s), especially if you don't use sudo or root.

prakhar@aS4v4g3wOrld:~$ ll /sbin/init
-rwxr-xr-x 1 root root 265848 Jul 18 15:16 /sbin/init*

The owner of /sbin/init is root. The only way you can modify this file is either via logging as root ($ sudo -s) or by giving an editor superuser permissions using sudo.

Besides, /sbin/init is a binary file, not meant for reading. If you still want to view this, use a hex editor like

$ sudo apt-get install ghex
$ ghex /sbin/init

Sure, you can read it without doing any harm.

It's a binary file - if you are interested in the text in it, like program symbols, messages, or version numbers, use strings:

strings /sbin/init | less

/lib64/ld-linux-x86-64.so.2
I*|YB
GU1q
nx#$
BDCE
#9ym
libnih.so.1
_ITM_deregisterTMCloneTable
__gmon_start__
_Jv_RegisterClasses
_ITM_registerTMCloneTable
nih_watch_new
nih_alloc_real_set_destructor
nih_timer_add_timeout
[ ... many more lines ... ]

To see the full binary content of the file in a somewhat readable form, use hexdump:

hexdump -C /sbin/init | less

00000000  7f 45 4c 46 02 01 01 00  00 00 00 00 00 00 00 00  |.ELF............|
00000010  03 00 3e 00 01 00 00 00  e9 96 00 00 00 00 00 00  |..>.............|
00000020  40 00 00 00 00 00 00 00  78 07 04 00 00 00 00 00  |@.......x.......|
00000030  00 00 00 00 40 00 38 00  09 00 40 00 1c 00 1b 00  |....@.8...@.....|
00000040  06 00 00 00 05 00 00 00  40 00 00 00 00 00 00 00  |........@.......|
00000050  40 00 00 00 00 00 00 00  40 00 00 00 00 00 00 00  |@.......@.......|
00000060  f8 01 00 00 00 00 00 00  f8 01 00 00 00 00 00 00  |................|
00000070  08 00 00 00 00 00 00 00  03 00 00 00 04 00 00 00  |................|
00000080  38 02 00 00 00 00 00 00  38 02 00 00 00 00 00 00  |8.......8.......|
00000090  38 02 00 00 00 00 00 00  1c 00 00 00 00 00 00 00  |8...............|
000000a0  1c 00 00 00 00 00 00 00  01 00 00 00 00 00 00 00  |................|
000000b0  01 00 00 00 05 00 00 00  00 00 00 00 00 00 00 00  |................|
000000c0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
000000d0  1c d7 03 00 00 00 00 00  1c d7 03 00 00 00 00 00  |................|
[ ... many more lines ... ]

You can view but you can't make changes. Do not save on exit init. copy the file first with

cp /sbin/init /sbin/init.me

then run

sudo nano /sbin/init.me

Here you first make a copy of the original file (init.me) then you take a look at init.me and find out what you are searching for.

Yep, it is fine to just view. Make sure when you click close, you don't save any changes you accidentally made.

To be super safe, run the following command:

sudo cp /sbin/init /tmp/init.copy

then run:

sudo gedit /tmp/init.copy

So you're not viewing the original.