Question

I’m trying to write a grep command that will match a python function declaration, in the form

def hello(hello)

so def, one space, a word that starts with either a letter, number or an underscore, open parenthesis, another word, closed parenthesis. I’m using the command

grep ^"def "[/-a-zA-z0-9][a-zA-z0-0]*[/(][a-zA-z0-9]*[/)]$ 

but I get a syntax error saying unrelated token near ( . I cant figure out what i’m doing wrong. any ideas?

Answer 1

I think there are a couple of mistakes. Here is what should work:

grep '^def [_a-zA-Z0-9][a-zA-Z0-9 ]*[\(][a-zA-Z0-9 ][a-zA-Z0-9 ]*[\)]$'

• I replaced your /- by underscore at the beginning of the regular expression
• I adjusted the backslash parenthesis
• I added some spaces in the classes in case it is needed
• I added a ‘[a-zA-Z0-9]’ after the opening parenthesis to guaranty at least one letter between parenthesis. You can remove it if you want to allow empty text in parenthesis