Single command to create a file and set its permission

Question

I am using the following 2 commands to create a 0B file and set its extn to 644

touch filename.ext
chmod 777 filename.txt

My question is that w

Answer 1

If you want to create the file not just empty but with content and mode at the same time you can use process substitution with install in bash:

install -m 755 <(echo commands go here) newscript

<() places the output into a temporary file (Process-Substitution)