Bash is notorious for chomping on precious trailing newline characters, making it tricky to set strings with newlines properly. In particular, the `$( exp )`_will trim trailing newlines_.
For instance to get this yaml:
```
a: |
cat
```
Using `$( exp )` wont work, as it will trim the trailing new line.
```
m=$(echo "cat\n") yq e -n '.a = strenv(m)'
a: cat
```
However, using printf works:
```
printf -v m "cat\n" ; m="$m" yq e -n '.a = strenv(m)'
a: |
cat
```
As well as having multiline expressions:
```
m="cat
" yq e -n '.a = strenv(m)'
a: |
cat
```
Similarly, if you're trying to set the content from a file, and want a trailing new line:
```
IFS= read -rd '' output <<(cat my_file)
output=$output ./yq e '.data.values = strenv(output)' first.yml
