Support bash $'ANSI-C quoted strings' in child_process.exec

[verhovsky]

• Version: v14.14.0
• Platform: Linux myhostname 5.8.0-44-generic path.resolve across drives in Windows #50-Ubuntu SMP Tue Feb 9 06:29:41 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

What steps will reproduce the bug?

const exec = require('child_process').exec;

exec("printf '%s' $'hello'", (error, stdout, stderr) => console.log(JSON.stringify(stdout)));

How often does it reproduce? Is there a required condition?

Always?

What is the expected behavior?

$ printf '%s' $'hello'
hello$ 

(there's no newline when using printf, that's why the $ is at the end instead of on the next line)

What do you see instead?

$ node /tmp/above_code_snippet.js
"$hello"
$

Additional information

ANSI strings in bash are documented here https://www.gnu.org/software/bash/manual/bash.html#ANSI_002dC-Quoting and work like this:

$ echo $'some\\ntext'
some\ntext
$ echo 'some\\ntext'
some\\ntext

See also yargs/yargs-parser#346

[aduh95]

I might be wrong but I think this feature is a bashism, not part of the standard POSIX shell. Note that the default shell is /bin/sh on Unix-like systems (see documentation), so you might want to specify a different one (probably the result of command -v bash).

import { exec } from 'child_process';

exec('command -v bash', (err, stdout) =>
  exec(
    "printf '%s' $'hello'",
    { shell: stdout.trim() },
    (error, stdout, stderr) => console.log(JSON.stringify(stdout))
  )
);

Anyway, I don't think this is a Node.js bug, exec is passing the string given straight to the shell, so there's nothing we can do here. Generally one would prefer to stick to POSIX-compliant shell code to ensure the code works everywhere, but if you are not concerned about distributability my suggested code should do just fine.

[RaisinTen]

I might be wrong but I think this feature is a bashism, not part of the standard POSIX shell.

I don't think this is a bug. This feature certainly does not work on sh:

$ echo $0
sh
$ printf '%s' $'hello'
$hello

[aduh95]

I'm going to close this as working as intended. Do not hesitate to ask more questions if needed or re-open if we misunderstood your issue.