Hello, When the -r, --no-run-if-empty option is combined with the -d, --delimiter or -0, --null options, the -r, --no-run-if-empty option does not take effect. The manual describes the intended behavior of the -r, --no-run-if-empty option: "If the standard input does not contain any nonblanks, do not run the command. Normally, the command is run once even if there is no input. This option is a GNU extension."
The following command correctly outputs nothing. xargs --no-run-if-empty -I str echo str <<< "" The following command incorrectly outputs 1 empty line. xargs --no-run-if-empty --delimiter="\n" -I str echo str <<< "" The following command incorrectly outputs 2 empty lines. xargs --no-run-if-empty --null -I str echo str <<< "" As a workaround according to this Stack Overflow answer <https://stackoverflow.com/a/17287097/3866835>, the following commands output nothing when the input consists only of whitespace. [[ $input = *[![:space:]]* ]] && xargs --delimiter="\n" -I str echo str <<< "$input" [[ $input = *[![:space:]]* ]] || xargs --null -I str echo str <<< "$input" Be well, Kurt von Laven
