Any line that has an 'abc' in it.

Regex: /abc/
Input: "abc xy"
Input: "abcde"
Input: "abxcxbdabce"
Input: "xabcde"
Input: "xa b c de"

Any line that starts with an 'abc'.

Regex: /^abc/
Input: "abcde"
Input: "abxcxbde"
Input: "xabcde"