The tree's README and fs.md answer round 8's doc questions

The README's log line names newcol, delcol, ask, restored and restoredcol;
it says what $m is under 9ns --unix; and a build that embeds no sources no
longer lists src/ (derived from the build, and tested). fs.md says what the
rest of a typed line does after Kill for each shell (fish runs on, bash
abandons it), that Exec <text> in a .py pane runs a command and never the
REPL, and why appending to a tag wants printf and a leading blank.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

3 files changed, 28 insertions, 9 deletions

diff --git a/docs/fs.md b/docs/fs.md
index 46fe9f86..742506f1 100644
--- a/docs/fs.md
+++ b/docs/fs.md
@@ -181,8 +181,10 @@ in a shell running without job control (`set +m`) the job shares the
 shell's group, so there is none to signal: Kill says `Kill: no job to
 signal`, and a write of it to `ctl` fails with that; with nothing running
 it says `Kill: nothing running`; and, of a typed line, only the
-foreground job, so of `sleep 30; echo done` typed at a prompt the `echo`
-still runs once the `sleep` is stopped --
+foreground job, after which what the rest of the line does is the shell's
+affair: of `sleep 30; echo done` typed at a prompt, fish goes on and runs
+the `echo`, and bash abandons the line, as each does when a job it waits
+on is killed --
 and reads every setting there is, one a line, in the words a write of it
 takes (`Verbose on`, `WindowOpacity 70`, `PanelSlide off`, `DumpDir
 <the directory in effect>`, `LocationsConfig ...`), so writing what it reads
@@ -344,7 +346,9 @@ terminal's while a program other than its shell holds the tty -- after
 Ctrl-D the shell would run the text, so nothing is sent and the pane says
 so. Still commands, whatever is bound: a word in a tag (so
 the tag is how to run `make` from that file), `Exec <text>` run by name
-(typed, a 2-1 chord onto `Exec`, a `ctl` line) and a command word @`cmd` in
+(typed, a 2-1 chord onto `Exec`, a `ctl` line) -- in a `.py` pane bound to
+a REPL, `Exec print(1)` runs `print(1)` as a command, never in the REPL --
+and a command word @`cmd` in
 the text, looked at or clicked (`# @`pytest -x`` in a script). A 9P `exec`
 is no gesture and is never sent: a script writes to the REPL pane's
 `pty/data`, multi-line code as a bracketed paste (`\e[200~<code>\e[201~`,
@@ -544,8 +548,10 @@ words (`Del`, `Put` and the rest) with it, since they are that text until
 you edit it, so `echo Make > tag` leaves only `Make` -- a truncating write
 drops the one newline that ends what it wrote, which would draw an empty
 row, and keeps any other; append with `>>` to
-keep them, with `printf ' Make' >> tag`: `echo` ends its word with a
-newline, which starts a new line of the tag. The clearing is an edit of the tag like a typed one and its undo
+keep them, with `printf ' Make' >> tag`. The leading blank is needed: the
+tag reads back with no blank after its last word, so `printf Make >> tag`
+glues `Make` onto it; and `echo ' Make' >> tag` ends with a newline, which
+starts a new line of the tag. The clearing is an edit of the tag like a typed one and its undo
 history is kept: `u` in the tag brings back the text it cleared, words
 included.
 
diff --git a/src/fs-help.txt b/src/fs-help.txt
index 08a7e262..73a49e9b 100644
--- a/src/fs-help.txt
+++ b/src/fs-help.txt
@@ -5,7 +5,8 @@ index       one line per pane: serial, kind (text|term|pdf|image), dirty flag, n
 status      pid, version and pane count
 look        write a line: a right click on it at the active pane; read: the serials it touched
 exec        write a line: a middle click, an editor command word or a shell line; read the same
-log         events: new/del/rename/save <serial> <name>, run/exit/send <serial> ..., dump/restore <path>, msg, err
+log         events: new/del/rename/save <serial> <name>, newcol/delcol <column serial>, run/exit/send <serial> ...,
+            ask <serial> <what> <choices>, dump/restore <path>, restored/restoredcol <old> <new>, msg, err
 screen      rendered screen as JSON, frozen from open to close
 listeners   the session's dial addresses
 focus       the serial of the pane with the keyboard (empty on a column tag); write a serial to give it the keyboard
@@ -18,9 +19,10 @@ col/<n>/ctl Delcol, Joincol, New or Tty on that column; col/<n>/exec a word as a
 pane/new    open it to make a pane (named +New) in the active column, filling it if empty; the read answers its serial
 pane/<n>/   name body tag ctl addr dot limit data xdata sel dirty mark scroll errors (write-only:
             appended to its directory's +Errors pane) event look exec, pty/ on terminals; rmdir closes
-os/, src/   the host filesystem; the editor's own sources (-Dembed-sources=true builds only)
+os/, src/   the host filesystem; the editor's own sources
 
-Below, $m is the mount: $NINE_MOUNT/pardes/<pid, or NAME of --detach=NAME>; PARDES_MOUNT in a Tty9p shell.
+Below, $m is the mount: $NINE_MOUNT/pardes/<pid, or NAME of --detach=NAME>; PARDES_MOUNT in a Tty9p shell;
+$NINE_MOUNT itself under `9ns --unix SOCKET -- cmd`, which mounts one session as its root.
 
   cat $m/index                                 which panes exist
   n=$(cat $m/pane/new)                        make a pane, take its serial
diff --git a/src/fs.zig b/src/fs.zig
index 65e5d276..8be728a6 100644
--- a/src/fs.zig
+++ b/src/fs.zig
@@ -19,7 +19,14 @@ const Reply = tree.Reply;
 const E = tree.E;
 
 /// The served README; tree.zig answers it.
-pub const help = @embedFile("fs-help.txt");
+/// The tree's README; a build that embeds no sources lists no src/.
+pub const help = help: {
+    const raw = @embedFile("fs-help.txt");
+    if (limits.embedded_sources) break :help raw;
+    const both = "os/, src/   the host filesystem; the editor's own sources";
+    const at = std.mem.indexOf(u8, raw, both) orelse @compileError("fs-help.txt no longer lists os/, src/");
+    break :help raw[0..at] ++ "os/         the host filesystem" ++ raw[at + both.len ..];
+};
 
 /// Host filesystem nodes: the root, and one hashed node per path a client walked to.
 pub const os_root: u64 = (1 << 63) + 2;
@@ -1364,3 +1371,7 @@ pub fn unmount(p: *Pardes, name: []const u8) !void {
 test {
     _ = tree;
 }
+
+test "the tree's README lists src/ only when the build serves it" {
+    try std.testing.expectEqual(limits.embedded_sources, std.mem.indexOf(u8, help, "src/") != null);
+}