CSV Bash循环变量问题

Question

I have a csv file which im trying to loop through with the purpose to find out if an User Input is found inside the csv data. I wrote the following code which sometimes works and others doesn't. It always stops working when I try to compare to a 2+ digit number. It works OK for numbers 1 through 9, but once u enter lets say 56 , or 99 or 100, it stops working.

the csv data is comma delimited, i have about 300 lines they are just like this.

1,John Doe,Calculus I,5.0
1,John Doe,Calculus II,4.3
1,John Doe,Physics II,3.5
2,Mary Poppins,Calculus I,3.7
2,Mary Poppins,Calculus II,4.7
2,Mary Poppins,Physics I,3.7

Data is just like that, all the way down until ID #100 for a total of 300 lines. Both the sh file and csv file are in the same folder, I'm using a fresh installation of Ubuntu 12.04.3, using gedit as the text editor.

I tried Echoing the variables ID and inside the IF conditionals but it doesn't behave the way it should when testing for the same value. Could someone point me out in the right direction. Thanks

Here's the code:

#s!/bin/bash
echo "enter your user ID";
read user;

INPUT_FILE=notas.csv
while IFS="," read r- ID name asignature final;
do
if [$ID = $user]; then
userType=1;
else
userType=2;
fi
done < notas.csv

Answer 1

You should quote your variables in the if test statement. You should also perform a numeric test -eq rather than a string comparison = . So your if statement should look like:

if [[ "$ID" -eq "$user" ]]

Answer 2

Well, your code as written has a few issues.

1. You have r- instead of -r on the read line - I assume that's a typo not present in your actual code or you wouldn't get very far.

2. Similarly, you need space around the [ ... ] brackets: [$ID is a syntax error.

3. You need to quote the parameter expansions in your if clause, and/or switch bracket types. You probably make it a numeric comparison as @imp25 suggested, which I would do by using (( ... )) .

4. You probably don't want to set userType to 2 in an else clause, because that will set it to 2 for everyone except whoever is listed last in the file (ID 100, presumably). You want to set it to 2 first, outside the loop. Then, inside the loop when you find a match, set it to 1 and break out of the loop:

    userType=2 while IFS=, read -r ID name asignature final; do if (( $ID == $user )); then userType=1; break fi done < notas.csv 

You could also just use shell tools like awk:

userType=$(awk -F, -vtype=2 '($1=="'"$user"'") {type=1}; END {print type}' notas.csv)

or grep :

grep -q "^$user," notas.csv
userType=$(( $? + 1 ))

etc.