unexpand

Convert spaces to tabs. More information: https://www.gnu.org/software/coreutils/unexpand.

• Convert blanks in each file to tabs, writing to stdout:
  unexpand {{path/to/file}}
• Convert blanks to tabs, reading from stdout:
  unexpand
• Convert all blanks, instead of just initial blanks:
  unexpand -a {{path/to/file}}
• Convert only leading sequences of blanks (overrides -a):
  unexpand --first-only {{path/to/file}}
• Have tabs a certain number of characters apart, not 8 (enables -a):
  unexpand -t {{number}} {{path/to/file}}