sh: write history on exit

Author: grisenti

sh/src/shell/history.rs

@@ -11,6 +11,7 @@ use crate::pattern::HistoryPattern;
 use crate::shell::environment::Environment;
 use std::collections::VecDeque;
 use std::io::Read;
+use std::io::Write;
 use std::path::Path;
 
 #[derive(Debug, Eq, PartialEq)]
@@ -218,6 +219,30 @@ fn read_history_from_file(path: &Path, max_entries: u32) -> History {
     }
 }
 
+pub fn write_history_to_file(history: &History, env: &Environment) {
+    let path = if let Some(histfile) = env.get_str_value("HISTFILE") {
+        histfile.to_string()
+    } else if let Some(home) = env.get_str_value("HOME") {
+        format!("{home}/.sh_history")
+    } else {
+        eprintln!("sh: HISTFILE or HOME not set, history not saved");
+        return;
+    };
+    match std::fs::File::options().write(true).open(&path) {
+        Ok(mut file) => {
+            for entry in &history.entries {
+                if let Err(err) = writeln!(file, "{}", entry.command) {
+                    eprintln!("sh: failed to write to history file at {} ({err})", path);
+                    return;
+                }
+            }
+        }
+        Err(err) => {
+            eprintln!("sh: failed to open history file at {} ({err})", path);
+        }
+    }
+}
+
 pub fn initialize_history_from_system(env: &Environment) -> History {
     let histsize = if let Some(histsize) = env.get_str_value("HISTSIZE") {
         histsize.parse().unwrap_or_else(|_| {

sh/src/shell/mod.rs

@@ -24,7 +24,7 @@ use crate::parse::word::WordPair;
 use crate::parse::word_parser::parse_word;
 use crate::parse::{AliasTable, ParserError};
 use crate::shell::environment::{CannotModifyReadonly, Environment, Value};
-use crate::shell::history::{initialize_history_from_system, History};
+use crate::shell::history::{initialize_history_from_system, write_history_to_file, History};
 use crate::shell::opened_files::OpenedFiles;
 use crate::signals::SignalManager;
 use crate::utils::{
@@ -194,6 +194,9 @@ impl Shell {
 
     pub fn exit(&mut self, code: i32) -> ! {
         self.execute_action(self.exit_action.clone());
+        if self.is_interactive && !self.is_subshell {
+            write_history_to_file(&self.history, &self.environment);
+        }
         std::process::exit(code);
     }