How to continue next iteration when an error occurs in Bash

Question

Below, you can find a bash script which must manage a csv file.

#!/bin/bash
IFS=";"

while read -a line;do
    printf "xxxxxxxxxxx Adresse: " >> retour.txt
    printf ${line[0]} >> retour.txt
    for i in ${line[@]}
    do
        if [ "$i" != "${line[0]}" ]
        then
            printf "\n port: " >> retour.txt
            printf $i >> retour.txt
            printf "\n" >> retour.txt
            nc ${line[0]} $i >> retour.txt 2>&1
        fi
    done
    printf "\n\n" >> retour.txt
done < Classeur.csv

Each line from the csv file contains the following things:

• an id
• a few ports which must be tested with the nc software.

When i launch the script, it stops after the first line. If i remove the following line from the code, everything is treated.

nc ${line[0]} $i >> retour.txt 2>&1

Nevertheless, the removed line contains the main operation... So, i guess it is an error from the line and i would like to know how i could go on when an error appears.

----------- 25/06/2018 ------

I have following the advices which are given by people comments. When i launch the code in debug mode, i get the following result:

 IFS=';'
 read -a line
 printf 'xxxxxxxxxxx Adresse: '
 printf xxx.xxx.xxx.238
 for i in '${line[@]}'
 '[' xxx.xxx.xxx.238 '!=' xx.xx.xx.238 ']'
 for i in '${line[@]}'
 '[' yyy1 '!=' xx.xx.xx.238 ']'
 printf '\n port: '
 printf yyy1
 printf '\n'
 nc -w 2 xxx.xxx.xxx?.238 yyyy
 telnet xxx.xxx.xxx.238 yyy1
 Trying xxx.xxx.xxx.238...
 Connected to xxx.xxx.xxx.238.
 Escape character is '^]'.
 Connection closed by foreign host.
 for i in '${line[@]}'
 '[' yyy5 '!=' xxx.xxx.xxx.238 ']'
 printf '\n port: '
 printf yyy5
 printf '\n'
 nc -w 2 xxx.xxx.xxx.238 yyy5
 telnet xxx.xxx.xxx.238 yyy5
 Trying xxx.xxx.xxx.238...
 telnet: connect to address xxx.xxx.xxx.238: Connection refused
 for i in '${line[@]}'
 '[' yyy6 '!=' xxx.xxx.xxx.238 ']'
 printf '\n port: '
 printf yyy6
 printf '\n'
 nc -w 2 xxx.xxx.xxx.238 yyy6
 telnet xxx.xxx.xxx.238 yyy6
 Trying xxx.xxx.xxx.238...
 telnet: connect to address xxx.xxx.xxx.238: Connection refused
 printf '\n\n'
 read -a line 

I have replaced the ip by xxx.xxx.xxx.238 and the port by values like : yyy1

It stops to the first line too.

Here is the csv file:

xxx.xxx.xxx.238;yyy1;yyy5;yyy6
xxx.xxx.xxx.82;yyy1;yyy5;yyy6
xxx.xxx.xxx.15;yyy6;yyy7;yyy0

Like you can see, it is only the first line which is used.

If i remove >> retour.txt and add , get the following text into the file which is created:

xxxxxxxxxxx Adresse: xxx.xxx.xxx.238
port: yyy1
Trying xxx.xxx.xxx...
Connected xxx.xxx.xxx.238.
Escape character is '^]'.
port: yyy5
Trying xxx.xxx.xxx.238...

port: yyy6
Trying 1xxx.xxx.xxx.238... 

It doesn't go on with the csv file second line.

----- THE FOLLOWING CODE IS THE SOLUTION -----

Finally, i arrived to solve the problem by following another way:

#!/bin/bash
IFS=";"
nbLines=$(cat classeur.csv | wc -l)
for ((j=1;j<=nbLines;j++))
do
        numRow="NR=="
        position=$numRow$j

        row=$(awk $position classeur.csv)
        IFS=" " read -ra TAB <<< $row
        for cell in "${TAB[@]}"
        do
                ipValeur=${TAB[0]}
                if [ "$cell" != "$ipValeur" ]
                then
                        printf "\n port: " >> retour.txt
                        printf $cell >> retour.txt
                        printf "\n" >> retour.txt
                        nc -w 2 $ipValeur $i >> retour.txt 2>&1
                else
                        printf "xxxxxxxxxxx Adresse: " >> retour.txt
                        printf $ipValeur >> retour.txt
                fi
        done
done