From 50fc850f165482a8304681e85a70ffb41dba731d Mon Sep 17 00:00:00 2001
From: Jonas Maier <>
Date: Thu, 5 Mar 2026 10:27:10 +0100
Subject: allow editing of prev command with backspace

---
 src/linebuf.rs | 10 ++++++++++
 src/main.rs    |  8 +++++++-
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/src/linebuf.rs b/src/linebuf.rs
index 15a8182..1d28549 100644
--- a/src/linebuf.rs
+++ b/src/linebuf.rs
@@ -4,6 +4,7 @@ use std::io::Write;
 pub struct LineBuf {
     pre: Vec<u8>,
     post: Vec<u8>,
+    dirty: bool,
 }
 
 #[allow(unused)]
@@ -12,14 +13,17 @@ impl LineBuf {
         Self {
             pre: Vec::new(),
             post: Vec::new(),
+            dirty: false,
         }
     }
 
     pub fn del_left(&mut self) -> Option<u8> {
+        self.dirty = true;
         self.pre.pop()
     }
 
     pub fn del_right(&mut self) -> Option<u8> {
+        self.dirty = true;
         self.post.pop()
     }
 
@@ -42,6 +46,7 @@ impl LineBuf {
     }
 
     pub fn add(&mut self, chr: u8) {
+        self.dirty = true;
         self.pre.push(chr);
     }
 
@@ -49,6 +54,10 @@ impl LineBuf {
         self.pre.is_empty() && self.post.is_empty()
     }
 
+    pub fn is_dirty(&self) -> bool {
+        self.dirty
+    }
+
     /// sets content all to the left
     pub fn set_content(&mut self, buf: Vec<u8>) {
         self.pre = buf;
@@ -60,6 +69,7 @@ impl LineBuf {
         while self.right() {}
         let mut buf = Vec::new();
         core::mem::swap(&mut self.pre, &mut buf);
+        self.dirty = false;
         buf
     }
 
diff --git a/src/main.rs b/src/main.rs
index 9d8f191..4e3bb23 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -195,7 +195,13 @@ fn main() {
 
             // Backspace (127 on most systems)
             127 => {
-                if line.del_left().is_some() {
+                if line.is_empty() && !line.is_dirty() && !history.is_empty() {
+                    // take previous command for editing
+                    let cmd = history[history.len() - 1].clone();
+                    io::stdout().write_all(&cmd).unwrap();
+                    io::stdout().flush().unwrap();
+                    line.set_content(cmd);
+                } else if line.del_left().is_some() {
                     print!("\x08 \x08");
                 }
             }
-- 
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