If by terminal programs you mean command-line interface (CLI) programs, then you'll never regret learning how core Unix commands work, in themselves and in pipelines, and their POSIX-defined interfaces. I use these often: make grep find sed xargs m4 cut tr cat tee sort uniq head tail pg/more/less ps pkill/pgrep. My favourite among them is make, once you learn how it's meant to be used, it's an incredibly useful and flexible tool.
Some other useful CLI programs that I use and are not part of POSIX are: strace, perl, webalizer, rcs. RCS might be a mostly-forgotten VCS tool, but it is very suitable for version-controlling projects that consist of single files. I mostly use it for plain-text or Org-mode documents.
If you meant terminal-UI (TUI) programs, like top/htop, vi, etc., I don't really use them. But I've used these in the past:
- mutt: a very nice mail client
- newsbeuter: RSS/ATOM feeds client
- vi: I do occasionally use vi in some situations
In the past years I've started to use Emacs tools instead of these because Emacs is a very rewarding, composable and comfortable working environment. Still, I use CLI programs through Bash/shell-mode all the time, because it's the most efficient way to do many tasks.
Some other useful CLI programs that I use and are not part of POSIX are: strace, perl, webalizer, rcs. RCS might be a mostly-forgotten VCS tool, but it is very suitable for version-controlling projects that consist of single files. I mostly use it for plain-text or Org-mode documents.
If you meant terminal-UI (TUI) programs, like top/htop, vi, etc., I don't really use them. But I've used these in the past:
- mutt: a very nice mail client
- newsbeuter: RSS/ATOM feeds client
- vi: I do occasionally use vi in some situations
In the past years I've started to use Emacs tools instead of these because Emacs is a very rewarding, composable and comfortable working environment. Still, I use CLI programs through Bash/shell-mode all the time, because it's the most efficient way to do many tasks.