Assignment asking to use grep command, how would I write a command when it is fine with the find command?

Question

My Intro to OS teacher wants me to enter a command that long lists the /etc directory and finds all files modified or created with the size of 4096 bytes.

My answer is simply find /etc -size 4k -ls .

How am I supposed to use the grep command to do this? It seems kind of pointless...

Answer 1

It sure makes no sense but in IT you kind of get used to insane seeming requirements so here is one:

$ ls -l /etc | grep "^-\([^ ]* *\)\{4\}4096 "
-rw-r--r--  1 root     root            4096 Oct 27  2014 wgetrc

• ^- it's a file ( ^d for dir etc.)
• [^ ]* * field and delimiting space(s)
• \\(...\\)\\{4\\} four times previous, ie. filesize is in the fifth field
• 4096 filesize. Notice the trailing space to limit the size exactly to 4096.