diff --git a/src/main.zig b/src/main.zig
index 0e704f4..2497ccc 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -34,13 +34,13 @@ pub fn main(init: process.Init) !void {
     });
     defer fern.deinit();
 
+    var rev_buf: [0x80]u8 = undefined;
     if (!maivi.dev)
-        maivi.rev = init.environ_map.get("MAIVI_REV") orelse rev_str(init.io, init.gpa, config.root) catch |e|
+        maivi.rev = init.environ_map.get("MAIVI_REV") orelse rev_str(init.io, &rev_buf, config.root) catch |e|
             blk: {
                 fern.warn().msg("version info cannot be retrieved from git. version must be provided using MAIVI_REV").err(e).log();
                 break :blk null;
             };
-    defer if (maivi.rev) |rev| init.gpa.free(rev);
 
     try maivi.init(init.io, init.gpa, &config);
     defer maivi.deinit();
@@ -57,12 +57,12 @@ pub fn main(init: process.Init) !void {
     try maivi.listen();
 }
 
-fn rev_str(io: Io, gpa: Allocator, root: []const u8) ![]const u8 {
+fn rev_str(io: Io, buf: []u8, root: []const u8) ![]const u8 {
     if (!process.can_spawn) {
         return error.NoChildProcess;
     }
 
-    const rev = try spawn(io, gpa, &[_][]const u8{
+    const rev = try spawn(io, buf, &[_][]const u8{
         "git",
         "-C", root, // affects the --git-dir argument
         "--git-dir", ".git", // affected by the -C argument
@@ -72,7 +72,7 @@ fn rev_str(io: Io, gpa: Allocator, root: []const u8) ![]const u8 {
     return std.mem.trim(u8, rev, std.ascii.whitespace[0..]);
 }
 
-fn spawn(io: Io, gpa: Allocator, argv: []const []const u8) ![]const u8 {
+fn spawn(io: Io, buf: []u8, argv: []const []const u8) ![]u8 {
     var child = try process.spawn(io, .{
         .argv = argv,
         .stdin = .ignore,
@@ -81,19 +81,17 @@ fn spawn(io: Io, gpa: Allocator, argv: []const []const u8) ![]const u8 {
     });
     errdefer child.kill(io);
 
-    var stdout_reader = child.stdout.?.readerStreaming(io, &.{});
-    const stdout = stdout_reader.interface.allocRemaining(gpa, .limited(0x80)) catch return error.ReadFailure;
-    errdefer gpa.free(stdout);
+    var rbuf: [0x80]u8 = undefined;
+    var stdout_reader = child.stdout.?.readerStreaming(io, &rbuf);
+    const n = try stdout_reader.interface.readSliceShort(buf);
 
     const term = try child.wait(io);
-    switch (term) {
-        .exited => |code| {
-            if (code != 0) {
-                return error.ExitCodeFailure;
-            }
-            return stdout;
-        },
-        .signal, .stopped => return error.ProcessTerminated,
-        .unknown => return error.ProcessTerminated,
-    }
+    return switch (term) {
+        .exited => |code| if (code != 0)
+            error.ExitCodeFailure
+        else
+            return buf[0..n],
+        .signal, .stopped => error.ProcessTerminated,
+        .unknown => error.ProcessTerminated,
+    };
 }