What will be matched by the following ed regular expressions? (Tip: If you're using them in other contexts, you should omit the backslashes

Question

*
[0-9]\{3\}
xx*
[0-9]\{3,5\}
x\{5,\}
^\...
x\{10\}
[A-Za-z_][A-Za-z_0-9]*
[0-9]*
^Begin$
[0-9][0-9][0-9]
^\(.\).*\1$

Answer 1

x*
Zero or more occurrences of the letter 'x'

[0-9]\{3\}
Three or more digits in a row

xx*
One or more occurrences of 'x'

[0-9]\{3,5\}
Exactly 3, 4 or 5 occurrences of a digit

x\{5,\}
Five or more occurrences of the letter 'x'

^\...
Any lines that start with a '.' and contain at least two additional characters

x\{10\}
Exactly 10 occurrences of the letter 'x'

[A-Za-z_][A-Za-z_0-9]*
An upper or lower case letter, or space, followed by zero or more occurrences of an upper or lower case letter, a digit or the underscore character

[0-9]*
Zero or more occurrences of a digit

^Begin$
Lines that contain "Begin" and nothing else before or after.

[0-9][0-9][0-9]
Any three digits in a row

^\(.\).*\1$
Any line that begins and ends with the same character