fix processing stdin with envset keys

CHANGELOG.md

@@ -0,0 +1,7 @@
+# changelog
+
+## [Unreleased]
+
+### Fixed
+
+- piping .env to stdin and running envset keys will now print the keys instead of writing them to .env

README.md

@@ -18,7 +18,7 @@ brew install schpet/tap/envset
 cargo install envset
 ```
 
-otherwise, grab the [latest release](https://github.com/schpet/envset/releases).
+otherwise, grab the [latest release](https://github.com/schpet/envset/releases/latest).
 
 ## usage
 

src/lib.rs

@@ -225,14 +225,18 @@ pub fn print_lines<W: Write>(lines: &[parser::Line], writer: &mut W, use_color:
 
 pub fn print_env_keys_to_writer<W: Write>(file_path: &str, writer: &mut W) {
     if let Ok(env_vars) = read_env_vars(file_path) {
-        for key in env_vars.keys() {
-            writeln!(writer, "{}", key).unwrap();
-        }
+        print_keys_from_map(&env_vars, writer);
     } else {
         eprintln!("Error reading .env file");
     }
 }
 
+pub fn print_keys_from_map<W: Write>(env_vars: &HashMap<String, String>, writer: &mut W) {
+    for key in env_vars.keys() {
+        writeln!(writer, "{}", key).unwrap();
+    }
+}
+
 pub fn delete_env_vars(
     content: &str,
     keys: &[String],

src/main.rs

@@ -7,8 +7,8 @@ use std::process;
 
 use envset::{
     add_env_vars, parse_args, parse_stdin, print_env_file_contents, print_env_keys_to_writer,
-    print_env_vars, print_env_vars_as_json, print_parse_tree, read_env_file_contents,
-    read_env_vars,
+    print_env_vars, print_env_vars_as_json, print_keys_from_map, print_parse_tree,
+    read_env_file_contents, read_env_vars,
 };
 
 fn print_diff(old_content: &str, new_content: &str, use_color: bool) {
@@ -128,7 +128,12 @@ fn main() {
             return; // Exit after printing
         }
         Some(Commands::Keys) => {
-            print_env_keys_to_writer(&cli.file, &mut std::io::stdout());
+            if !atty::is(Stream::Stdin) {
+                let env_vars = parse_stdin();
+                print_keys_from_map(&env_vars, &mut std::io::stdout());
+            } else {
+                print_env_keys_to_writer(&cli.file, &mut std::io::stdout());
+            }
         }
         Some(Commands::Delete { keys }) => match read_env_file_contents(&cli.file) {
             Ok(old_content) => match envset::delete_env_vars(&old_content, keys) {