how to continue with the loop even though we use exit for a condition in shell script - shell

Question

I have a following list.txt file with the content
cat list.txt
one
two
zero
three
four
I have a shell script (check.sh) like below,
for i in $(cat list.txt)
do
if [ $i != zero ]; then
echo "the number is $i"
else
exit 1
fi
done
it gives output like below,
./check.sh
the number is one
the number is two
I want to have script which continue with the rest of the items in the list.txt, but it should not process zero and continue with the rest of item.
eg.
the number is one
the number is two
the number is three
the number is four
I tried using "return" but it did not work, gave error.
./check.sh: line 6: return: can only `return' from a function or sourced script

Answer 1

About exit (and return)
The command exit will quit running script. There is no way to continue.
As well, return command will quit function. There in no more way to continue.
About reading input file
For processing line based input file, you'd better to use while read instead of for i in $(cat...:
Simply try:
while read -r i;do
if [ "$i" != "zero" ] ;then
echo number $i
fi
done <list.txt
Alternatively, you could drop unwanted entries before loop:
while read -r i;do
echo number $i
done < <( grep -v ^zero$ <list.txt)
Note: In this specific case, ^zero$ don't need to be quoted. Consider quoting if your string do contain special characters or spaces.
If you have more than one entries to drop, you could use
while read -r i;do echo number $i ;done < <(grep -v '^\(zero\|null\)$' <list.txt)
Alternatively, once input file filtered, use xargs:
If your process is only one single command, you could avoid bash loop by using xargs:
xargs -n 1 echo number < <(grep -v '^\(zero\|null\)$' <list.txt)
How to use continue in bash script
Maybe you are thinking about something like:
while read -r i;do
if [ "$i" = "zero" ] ;then
continue
fi
echo number $i
done <list.txt
Argument of continue is a number representing number of loop to shortcut.
Try this:
for i in {1..5};do
for l in {a..d};do
if [ "$i" -eq 3 ] && [ "$l" = "b" ] ;then
continue 2
fi
echo $i.$l
done
done
(This print 3.a and stop 3 serie at 3.b, breaking 2 loop level)
Then compare with
for i in {1..5};do
for l in {a..d};do
if [ "$i" -eq 3 ] && [ "$l" = "b" ] ;then
continue 1
fi
echo $i.$l
done
done
(This print 3.a , 3.c and 3.d. Only 3.b are skipped, breaking only 1 loop level)