How do I invoke deno from a shell script?

Question

I have a script I'd like to run... maybe something like this:

#!/usr/bin/env deno

console.log('hello world');

The shebang part is confusing. When I do it as above, with the filename dev, I get:

error: Found argument './dev' which wasn't expected, or isn't valid in this context

When I try to change the shebang to #!/usr/bin/env deno run

I get

/usr/bin/env: ‘deno run’: No such file or directory

Any thoughts on how to pull this off?

https://stackoverflow.com/questions/3009192/how-does-the-shebang-work — William Pursell, Jul 22 '20 at 22:14
Google suggests that deno needs the executable to have a `.js` or `.ts` extension — that other guy, Jul 22 '20 at 22:16

score 11 · Accepted Answer · edited Dec 12 '21 at 02:04

11

In order to pass command options to deno via env, you need the -S parameter for env.

For example, the following is the minimal shebang you should use for self-running a script with Deno.

#!/usr/bin/env -S deno run

Complex Example:

The following script/shebang will run Deno as silently as possible, with all permissions and will assume there is an import_map.json file next to the script file.

#!/usr/bin/env -S deno -q run --allow-all --import-map="${_}/../import_map.json"

// get file and directory name
const __filename = import.meta.url.replace("file://", "");
const __dirname = __filename.split("/").slice(0, -1).join("/");

The lines with __filename and __dirname will give you variables similar to Node's execution.

Script Installer

Deno also provides a convenient method for installing a script with it's permissions and dependencies in the configured distribution location.

See: Deno Manual - Script installer

Stand-Alone Executable

As of Deno 1.6, you can now build stand-alone executables from your script as well.

See: Deno Manual - Compiler - Compiling Executables

edited Dec 12 '21 at 02:04

Martin Braun

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answered Jul 22 '20 at 22:32

dwmorrin

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Yes, I understand that. I'm trying to write shell scripts using deno / javascript. When I run that install, it just makes a shell script that invokes deno run. Is it possible to do that natively inside a shell script? – RandallB Jul 23 '20 at 09:30
1

@RandallB - Thanks for clarifying that you already knew about `deno install`. I updated my answer. – dwmorrin Jul 23 '20 at 10:25
What if I don't have the `-S` option? – Sean Nov 17 '20 at 01:35
@Sean then it won't work... to use `/usr/bin/env` with `deno run` as the command, you must have `-S` in between on the shebang line. I've updated the answer with a more complex example, as well as a minimal example. – Tracker1 Apr 12 '21 at 05:34

score 1 · Answer 2 · answered Dec 08 '20 at 18:39

1

Deno 1.6.0

can compile to a standalone binary / executable file, no need for a custom Shebang:

$ deno compile --unstable main.js 
# or add custom output path
$ deno compile --unstable main.js -o /my/path/main
# both create ./main executable (e.g. on Linux)

# execute script directly
$ ./main

More infos

feat: deno compile #8539 (PR)
Deno v1.6.0 (release info)
"deno compile" into executable #986 (feature request)

answered Dec 08 '20 at 18:39

ford04

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When you provide Deno scripts that should be open-source (like helper scripts in a public repository), there is a need to use a custom Shebang, instead of compilation, definitely. – Martin Braun Jul 23 '21 at 23:52