grep each line in a file

Question

I have two files: one is a fairly long collection of names (names.txt), and another file (grades.csv) which is a huge file of names and the corresponding grades. I would like to iterate over each line in names.txt and extract that name in grades.csv with the entire matching line.

This is how a small sample names.txt looks like

"Dumbledore, Albus"
"Potter, Harry"
"Riddle, Tom

Here is the structure of a dummy grades.csv file

"Granger, Hermione", 96.65%, 9,10
"Mcgonagall, Minerva", 80.43%, 6,7
"Dumbledore, Albus", 100%, 8, 9
"Potter, James", 91%, 7,89
"Ravenclaw, Rowena", 32%, 4,56
"Potter, Harry", 34%, 56,67
"Riddle, Tom", 99%, 3,4

I'd like to extract each line of names.txt and search grades.csv to get this

"Dumbledore, Albus", 100%, 8, 9
"Potter Harry", 34%, 56,67
"Riddle Tom", 99%, 3,4

I know I would have to use grep/awk/sed for this (I am using a Linux environment) but I don't know how to use grep to loop over the lines in a file, since I am not very good at the bash command terminal. Any help appreciated!

Answer 1

I made some changes to your names.txt and grades.csv - some of the names are comma-separated and some aren't. I removed commas within quotes, so here are the new files:

22:46 $ cat names.txt 
"Dumbledore Albus"
"Potter Harry"
"Riddle Tom"

22:46 $ cat grades.csv 
"Granger Hermione", 96.65%, 9,10
"Mcgonagall Minerva", 80.43%, 6,7
"Dumbledore Albus", 100%, 8, 9
"Potter James", 91%, 7,89
"Ravenclaw Rowena", 32%, 4,56
"Potter Harry", 34%, 56,67
"Riddle Tom", 99%, 3,4

You can use grep with a file argument -f:

22:46 $ cat script.sh 
#!/bin/bash
names="/path/to/names.txt"
grades="/path/to/grades.csv"
grep -f <(tr ',' '\n' < "${names}") "${grades}"

This gives me the following output:

22:46 $ ./script.sh 
"Dumbledore Albus", 100%, 8, 9
"Potter Harry", 34%, 56,67
"Riddle Tom", 99%, 3,4

EDIT

Assuming the names.txt and grades.csv as a rule are formatted as "Lastname, Firstname" case-insensitively:

#!/bin/bash
names="/path/to/names.txt"
grades="/path/to/grades.csv"
grep -fi "${names}" "${grades}"

Answer 2

Try this:

  while read l; do grep -i "${l//\"/}" grades.csv; done < names.txt 

I tested it with bash on Ubuntu 14.04. The output:

$ while read l; do grep -i "${l//\"/}" grades.csv; done < names.txt 
"Dumbledore, Albus", 100%, 8, 9
"Potter, Harry", 34%, 56,67
"Riddle, Tom", 99%, 3,4