tmux/Session/Q/How can I give the session name more room in the status line?

• How can I give the tmux/session/Name more room in the tmux/Status Line?

  • AI Answer

    • Short answer: raise tmux/Option/status-left-length. One line in ~/.config/tmux/tmux.conf (tmux/Config):
      • sh

        set -g status-left-length 40

    • What is doing the cutting

      • tmux/Option/status-left is [#{session_name}] , so a name of N characters wants N + 3 columns.
      • status-left-length defaults to 10, and status-format[0] applies it as #{T;=/#{status-left-length}:status-left} — keep the first ten characters, discard the rest. The bracket takes one of them, so nine characters of the session name survive, and the closing ] is never reached: encode-2026-08-17 draws as [encode-20.
      • Nothing else is narrowing it. The default status-left has no per-cell =N: limit inside the format string, so the length cap is the only bound on the name. A per-cell limit would survive any change to the cap.

    • What it costs

      • The cap is a maximum, not a reservation: with status-justify left the window list starts immediately after whatever the left component actually drew, so the columns come out of the window list, and only for sessions whose names are long.

      • Session name	Left component drawn	Columns	Beyond the default
        gardening	[gardening]	12	2
        cos-2026-08-17	[cos-2026-08-17]	17	7
        encode-2026-08-17	[encode-2026-08-17]	20	10
        mn-kb chief of staff 2026-08-17 mon	[mn-kb chief of staff 2026-08-17 mon]	38	28

      • Nothing is lost until the three parts together exceed the client width, at which point the window list is what gets the < and > scroll markers. A six-window session with a 107-column window list and a 39-column right component needs 163 columns at a 17-column left, against 156 at the default cap — so a 191-column terminal has room to spare.
      • The numbers for any given client:
        • sh

          tmux display-message -p '#{client_width}'
          tmux display-message -p '#{w:#{T:status-left}}'
          tmux display-message -p '#{w:#{T:status-right}}'

    • Where to find more columns

      • Drop the brackets from status-left for two more characters of name per session:
        • sh

          set -g status-left '#{session_name} '

      • Take eleven columns off the right end by shortening the pane-title cell in tmux/Option/status-right, then bringing tmux/Option/status-right-length down to match:
        • sh

          set -g status-right '"#{=10:pane_title}" %H:%M %d-%b-%y'
          set -g status-right-length 30

      • Shorten the window names when the window list is the part under pressure — each one costs its index, a colon, its name and a flag column, plus a separator.

    • Sources

      • tmux(1) man page — status-left-length, status-right-length, status-justify, FORMATS