Shell quoting for recipes that compose command text.
A recipe splices its values into a command a shell reads: a script's check
and run, or a script it writes to a file. Each value goes in as one
single-quoted word, inside which a shell reads every byte literally except a
single quote — so a value can't change what the command means, whatever it
holds ($, backticks, ", ;, spaces, newlines).
A value may be a reference (env_ref / zap.env). Its marker holds no single
quote, so it lands inside the quotes, and zap refuses to resolve a reference
whose value holds one when the command runs. A literal single quote in the
text is escaped ('\''), which is what it means inside single quotes.
A pure function, like the recipes that import it: it only assembles a string.
2 declarations
(value: string): string import {single_quote} from '@fuzdev/zap/shell.js'; value as one single-quoted shell word, each ' in it written '\''.
The twin of zap's own quoting for the values it composes into commands, so a recipe's command quotes the way zap's do.
valuethe text, literal or holding references
stringstring the quoted word
(recipe: string, user: string): string import {sudo_as_user} from '@fuzdev/zap/shell.js'; The sudo -u <user> prefix of a command a recipe runs as user, refusing a user
that wouldn't name the account the recipe means.
sudo -u reads a user starting with # as a uid (#0 is root), and an empty one
as nothing at all. A reference (env_ref / zap.env) is refused too: its value
isn't known until the command runs, so a recipe can't check it, and a value of #0
would run the command as root.
recipethe recipe's name, for the error
stringuserthe account's name
stringstring sudo -u and the quoted name, then a space
Error - if `user` is empty, starts with `#`, or holds a reference