input =
This is an example text with some spaces.
This should be 2nd line.
However the spaces between "quotes should not change".
last line.
output =
Thisisanexampletextwithsomespaces.
Thisshouldbe2ndline.
Howeverthespacesbetween"quotes should not change".
lastline.
awk '
BEGIN {FS = OFS = "\""}
/^[[:blank:]]*$/ {next}
{for (i=1; i<=NF; i+=2) gsub(/[[:space:]]/,"",$i)}
1
'
Thisisanexampletextwithsomespaces.
Thisshouldbe2ndline.
Howeverthespacesbetween"quotes should not change".
lastline.