I want split the string with delimiter comma and write it to a file. I have the below script but when I see the output(temp.txt) I see the complete for loop code written to file.. Can anyone help me to fix this issue
#!/bin/bash -e
string1=a/b,b/c,c/d
IFS=', ' read -a array <<< "$string1"
cat << 'EOF' > temp.txt
for element in "${array[@]}"
do
echo "$element"
done
EOF
a/b
b/c
c/d
Use printf:
#!/bin/bash -e
string1=a/b,b/c,c/d
IFS=', ' read -ra array <<< "$string1"
printf '%s\n' "${array[@]}" > temp.txt
And the longer way:
for e in "${array[@]}"; do
echo "$e"
done > temp.txt
Another using IFS:
IFS=$'\n' eval 'echo "${array[*]}" > temp.txt'
Note: Changing the IFS is unnecessary but if you want to strictly split the string with commas, change it to IFS=,:
IFS=, read -ra array <<< "$string1"
printf approach and shows a series of additional correct answers (with the caveat that the echo version wouldn't work correctly with -E or -n as data on account of bash's non-POSIX behavior). Also, this is interesting to me as a demonstration of a place where eval is entirely safe and useful.Your IFS is incorrect, there should be no space. Also, you can just indirect the output of the loop to the file:
#!/bin/bash -e
string1=a/b,b/c,c/d
IFS=',' read -a array <<< "$string1"
for element in "${array[@]}"
do
echo "$element"
done > temp.txt
If your only intention is to turn commas into newlines, you could use something simple like tr:
tr , '\n' <<<"$string1" > temp.txt
You could also use the -d option of the read builtin command in a loop like this:
while read -d, -r; do
echo "$REPLY"
done <<<"$string1," > temp.txt
You'll notice that I added a , to the end of the string1 expansion as -d is substituting , for a newline character.
Although it requires a bit more code, you could avoid adding the extra comma to the here string by doing another echo $REPLY after the loop.
{ while read -d, -r; do
echo "$REPLY"
done <<<"$string1"
echo $REPLY
} > temp.txt
You could also just use a subshell to echo your array with a newline IFS:
IFS=, read -ra array <<<"$string1"
(IFS=$'\n'; echo -e "${array[*]}") > temp.txt
$REPLY one more time after the loop ends (because read returns non-zero on EOF). Though that's likely less useful of a pattern.