CmdID / Commands
Soak up the input before writing the output file. tldr-pages
On several platforms
Opens CmdID with your command. It is read in your browser and sent nowhere.
Append file content to the source file
cat path/to/file | sponge -a path/to/file
Remove all lines starting with # in a file
grep --invert-match '^#' path/to/file | sponge path/to/file