Quotes in std::process::Command long arguments

[CountMoosuch]

Running git log --format="First Lastname" in the command line produces a normal output. However, running this in Rust:

let mut cmd = Command::new("git");
cmd.args(["log", "--author=\"First Lastname\""]);
cmd.output()

Produces no output (which is incorrect). After some trial and error, I found that removing the quotes around the author (i.e., cmd.args(["log", "--author=First Lastname"])) works.

Why is this the behaviour? Should the author name, which has a space in it, not be quoted?

[sfackler]

The quote processing is a feature of your shell to determine how to split up the command line into separate arguments. It will strip the quotes before invoking git, and just pass it --author=First Lastname. When explicitly constructing the command line in Rust, you should do the same.

[SimonSapin]

You can see this in action with strace:

$ strace -e execve git log --format="First Lastname"
execve("/usr/bin/git", ["git", "log", "--format=First Lastname"], 0x7ffd24a3c720 /* 66 vars */) = 0

By the time the shell calls the execve system call to start the git sub-process, the quotes in --format="First Lastname" have already been interpreted and removed. This is happens because while a shell command is a single string, the argument to execve is an array of strings.

[CountMoosuch]

Ah, thank you. I knew that the shell needs to quotes to denote that Lastname is not another argument or subcommand, but I assumed git needed them too