A column has a ctl, an exec and an rmdir over 9P, and Restore maps its serial

A script could read and write a column's tag but not act on the column.
col/<serial>/ctl takes Delcol, Joincol, New and Tty, each acting on that
column as from its tag; col/<serial>/exec runs a word as a middle click in
the tag; rmdir col/<serial> closes an empty column and refuses one with
panes (ENOTEMPTY, an err record saying why). The root ctl's refusal of
Delcol and Joincol points at col/<serial>/ctl. A dump keeps each column's
serial and Restore logs restoredcol <old> <new>; the dump golden gains
them. Documented: Joincol's survivor, the column on the right, keeps its
serial and tag.

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

1 files changed, 1 insertions, 0 deletions

diff --git a/src/fs-help.txt b/src/fs-help.txt
index 50e9e7fc..08a7e262 100644
--- a/src/fs-help.txt
+++ b/src/fs-help.txt
@@ -14,6 +14,7 @@ commands    every builtin: its word, arg if it takes one, and root or pane: whic
 layout      one line per column: serial index x width current|notcurrent empty|full pane-serials...; then active <serial>
 tag         the workspace tag: read it, > replaces it, >> appends (one line)
 col/<n>/tag the tag of the column with serial n, the same way (a serial stays while the column lives)
+col/<n>/ctl Delcol, Joincol, New or Tty on that column; col/<n>/exec a word as a click in its tag; rmdir col/<n> closes an empty one
 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