feat: add gix env to print paths relevant to the Git installation.

Author: Byron

Diff for: gitoxide-core/src/lib.rs

@@ -30,6 +30,7 @@
 #![deny(rust_2018_idioms)]
 #![forbid(unsafe_code)]
 
+use anyhow::bail;
 use std::str::FromStr;
 
 #[derive(Debug, Eq, PartialEq, Hash, Clone, Copy)]
@@ -82,6 +83,51 @@ pub mod repository;
 mod discover;
 pub use discover::discover;
 
+pub fn env(mut out: impl std::io::Write, format: OutputFormat) -> anyhow::Result<()> {
+    if format != OutputFormat::Human {
+        bail!("JSON output isn't supported");
+    };
+
+    let width = 15;
+    writeln!(
+        out,
+        "{field:>width$}: {}",
+        std::path::Path::new(gix::path::env::shell()).display(),
+        field = "shell",
+    )?;
+    writeln!(
+        out,
+        "{field:>width$}: {:?}",
+        gix::path::env::installation_config_prefix(),
+        field = "config prefix",
+    )?;
+    writeln!(
+        out,
+        "{field:>width$}: {:?}",
+        gix::path::env::installation_config(),
+        field = "config",
+    )?;
+    writeln!(
+        out,
+        "{field:>width$}: {}",
+        gix::path::env::exe_invocation().display(),
+        field = "git exe",
+    )?;
+    writeln!(
+        out,
+        "{field:>width$}: {:?}",
+        gix::path::env::system_prefix(),
+        field = "system prefix",
+    )?;
+    writeln!(
+        out,
+        "{field:>width$}: {:?}",
+        gix::path::env::core_dir(),
+        field = "core dir",
+    )?;
+    Ok(())
+}
+
 #[cfg(all(feature = "async-client", feature = "blocking-client"))]
 compile_error!("Cannot set both 'blocking-client' and 'async-client' features as they are mutually exclusive");
 

Diff for: src/plumbing/main.rs

@@ -146,6 +146,15 @@ pub fn main() -> Result<()> {
     }
 
     match cmd {
+        Subcommands::Env => prepare_and_run(
+            "env",
+            trace,
+            verbose,
+            progress,
+            progress_keep_open,
+            None,
+            move |_progress, out, _err| core::env(out, format),
+        ),
         Subcommands::Merge(merge::Platform { cmd }) => match cmd {
             merge::SubCommands::File {
                 resolve_with,

Diff for: src/plumbing/options/mod.rs

@@ -145,6 +145,7 @@ pub enum Subcommands {
     Corpus(corpus::Platform),
     MergeBase(merge_base::Command),
     Merge(merge::Platform),
+    Env,
     Diff(diff::Platform),
     Log(log::Platform),
     Worktree(worktree::Platform),