Emacs shell scripts – how to put initial options into the script?

by

Many unix variants only allow a single argument to the program on the shebang line. Sad, but true. If you use #!/usr/bin/env emacs so as not to depend on the location of the emacs executable, you can’t pass an argument at all.

Chaining scripts is a possibility on some systems, but that too is not supported everywhere.

You can go the time-honored route of writing a polyglot script: a script that is both a shell script and an Emacs Lisp script (like Perl’s if $running_under_some_shell, for example). It sure looks hackish, but it works.

Elisp comments begin with ;, which in the shell separates two commands. So we can use a ; followed by a shell instruction to switch over to Emacs, with the actual Lisp code beginning on the next line. Most shells don’t like an empty command though, so we need to find something that both the shell and Emacs treat as a no-op, to put before the ;. The shell no-op command is :; you can write it ":" as far as the shell is concerned, and Emacs parses that as a constant at top level which is also a no-op.

#! /bin/sh
":"; exec emacs --no-site-file --script "$0" -- "$@" # -*-emacs-lisp-*-
(print (+ 2 2))

More Related Contents:

  1. Is there a “standard” format for command line/shell help text?
  2. shell – remove numbers from a string column [closed]
  3. What’s the difference between .bashrc, .bash_profile, and .environment?
  4. How can I parse a YAML file from a Linux shell script?
  5. How to read a file into a variable in shell?
  6. Shell command to sum integers, one per line?
  7. How to make grep only match if the entire line matches?
  8. How can I execute a command stored in a variable?
  9. What does $$ mean in the shell?
  10. Unix time and leap seconds
  11. What is the $? (dollar question mark) variable in shell scripting? [duplicate]
  12. How to insert a newline in front of a pattern?
  13. How do you tell if a string contains another string in POSIX sh?
  14. commands not found on zsh [closed]
  15. How to mark a build unstable in Jenkins when running shell scripts
  16. Rearrange columns using cut
  17. How to pass arguments to Shell Script through docker run
  18. is it possible to use variables in remote ssh command?
  19. Trim leading and trailing spaces from a string in awk
  20. How to grep a text file which contains some binary data?
  21. Can I call a function of a shell script from another shell script?
  22. nginx: use environment variables
  23. How can I run Cygwin Bash Shell from within Emacs?
  24. Read file into String and do a loop in Expect Script
  25. How to keep dir-local variables when switching major modes?
  26. How to run a shell script on every request?
  27. Is there a way to get my emacs to recognize my bash aliases and custom functions when I run a shell command?
  28. Unix shell script find out which directory the script file resides?
  29. Emacs – Error when calling (server-start)
  30. How do I do closures in Emacs Lisp?

Leave a Comment