Homework & Coursework Questions

Hello, i am in need of assistance with a linux homework.

1. The problem statement, all variables and given/known data:
I must print out all the lines which have an uneven number of characters([number of characters on line]%2=1)

2. Relevant commands, code, scripts, algorithms:
GREP


3. The attempts at a solution (include all code and scripts):

I have read most of the manual and still not able to come up with a solution to count characters using grep. Very important: using grep is a must.

4. Complete Name of School (University), City (State), Country, Name of Professor, and Course Number (Link to Course):
Universitatea Babes Bolyai Facultatea de Matematica si Informatica, Cluj-Napoca,Romania,Dr. Boian Florian(the course is in Romanian, so i figure it's useless to post a link here)

Note: Without school/professor/course information, you will be banned if you post here! You must complete the entire template (not just parts of it).

I would guess your prof is more interested in how to construct a regular expression to eliminate odd or even numbers of characters. Have you done regular expressions (regex) in class? Or character classes e.g., '[0-9]' means for all digits?
e.g. -

Code:

'^[a-z]{10}$'

What does this regex do?

I am not sure if there is any method to use grep alone for counting the number of characters.

But you can use grep along with wc to count number of characters.

Here is an example:

Code:

$ printf "BAPaul" | grep -o "." | wc -l
6

Code:

-o      Only matching
"."     Match any single character
wc -l   Print the newline counts

I disagree with the previous responses. There's definitely a way to do it. Took me just a few seconds to "get it", at least one way. And it's not a "trick question". This is a very good question your professor asked.

My understanding is I'm not supposed to just give the answer. I'm sure you can figure it out if you understand regular expressions. Do you understand regular expressions?

I'll give a clue. The regular expression is relatively short.

Before you try to solve the problem, your first step should be to build a test file to confirm if your solution works or not. Could you provide the test file?

I agree with hanson44; this can be done with grep alone. A good question.
Another clue: Read up on quantifiers in regular expressions.

LOL and agreed - it is very short!

Yet another clue would be that you might want to revisit the assumption that you need to count characters...