How to filter results from a csv file based on patterns in columns 1 and 7 using sed?

Question

I'm trying to write a shell script that scans both columns 1 and 7 for user-specified values, with $3 being matched in 7th column and $2 being a year matched in first column (and $1 the filename). I can match the 7th col just fine, but keep receiving the error 'sed: -e expression #1, char 7: unknown command: `2' when attempting to add the variable to match in first column. I have to use sed instead of awk for this unfortunately. Here's what I have thus far:

sed -n "/"$2",[^,],[^,],[^,],[^,],[^,]*,"$3"/p" "$1"

what should I try to fix this? I'm quite a noobie so all help is welcome. Tried shellcheck but it hasn't helped. The script runs fine when scanning 7th column but adding the $2 aspect causes errors.

Edit: Sample invocation:

./script.sh filename "2015.2016" "South"

Sample file (with "..." being a column with text inside):

2021/2022,text,text,text,text,text,South,text,...,...
2021/2022,text,text,text,text,text,North,text,...,...
2015/2016,text,text,text,text,text,South,text,...,...
2014/2015,text,text,text,text,text,West,text,...,...

Intended output:

2015/2016,text,text,text,text,text,South,text,...,...

Edit: While I agree that it's indeed not the best tool for the job, I figured out how to accomplish this with sed after playing around a bit:

#!/bin/bash

year="$2"
name="$3"

sed -n '/^'"$year"',\([^,]*,\)\{5\}'"$name"'\(,.*\)\{0,\}$/p' "$1" 

Dunno if I'll ever make use of it but maybe it will help someone else out. Note that the input needs a "." rather than "/" in order to yield accurate result.

Answer 1

sed isn't a good tool for this, just use awk:

$ cat script.sh
#!/usr/bin/env bash

awk -F',' '$1==a && $7==b' a="$2" b="$3" "$1"

$ ./script.sh file.csv "2021" "South"
2021,text,text,text,text,text,South,text

Since you need a sed solution, though, using a POSIX sed:

$ cat script.sh
#!/usr/bin/env bash

a=$(sed 's/[^^\\]/[&]/g; s/\^/\\^/g; s/\\/\\\\/g' <<< "$2")
b=$(sed 's/[^^\\]/[&]/g; s/\^/\\^/g; s/\\/\\\\/g' <<< "$3")
sed -n '/^'"$a"',\([^,]*,\)\{5\}'"$b"'\(,.*\)\{0,\}$/p' "$1"

$ ./script.sh file.csv "2021" "South"
2021,text,text,text,text,text,South,text

See is-it-possible-to-escape-regex-metacharacters-reliably-with-sed for why the first 2 sed commands are necessary but in short it's because you need to do a literal string match while sed only supports regexp matches, not literal string matches, so you have to escape every possible regexp metachar (actually you have to escape every char as any char could be the sed script delimiter, e.g. /) to make it act like a literal char. That is the 2nd big clue that sed is the wrong tool for the job (the first being that it doesn't split input into fields) vs a tool such as awk that simply supports literal string matches.