grep -im1

 Grep is very important command. Let's try with m!

[winetou@server01 check_ssh]$ cat list.txt | grep -im3 so

sopka103

sopka104

sopka105

[winetou@server01 check_ssh]$ cat list.txt | grep -im4 so

sopka103

sopka104

sopka105

sopka106

grep -i = ignore case sensitive

grep -m = max-count=NUM

(from man)

Thank you Martin!