Formats in tmux

1. b: and d: (Basename and Dirname)

• Purpose: Extracts the basename (filename) and dirname (directory path) from a file path.
• Examples:
  • Basename (b:):
    • Given: #{b:/usr/local/bin/tmux}
    • Result: tmux (extracts just the filename).
  • Dirname (d:):
    • Given: #{d:/usr/local/bin/tmux}
    • Result: /usr/local/bin (extracts the directory path).

2. q: (Escape Special Characters)

• Purpose: Escapes shell special characters; q:h escapes hash characters.
• Examples:
  • Escape Special Characters (q:):
    • Given: #{q:This # is special}
    • Result: Escapes the # to be interpreted literally.
  • Escape Hash (q:h):
    • Given: #{q:h#}
    • Result: ## (makes # become ##).

3. E: (Double Expansion)

• Purpose: Expands the format twice, useful for nested formats.
• Example:
  • Given: #{E:status-left}
  • Result: Expands the content of the status-left option rather than the option itself.

4. T: (Time Expansion)

• Purpose: Similar to E:, but also expands strftime time specifiers.
• Example:
  • Given: #{T:%Y-%m-%d %H:%M:%S}
  • Result: Shows the current date and time.

5. S:, W:, P: (Looping Formats)

• Purpose: Loops over sessions, windows, or panes and applies the format to each.
• Examples:
  • Windows Looping (W:):
    • Given: #{W:#{window_index} ,#{window_active}}
    • Result: Lists window indices, with a special format for the active window.

6. N: (Existence Check)

• Purpose: Checks if a named window or session exists.
• Example:
  • Given: #{N/w:foo}
  • Result: Replaced with 1 if a window named foo exists, otherwise 0.

7. s/foo/bar/: (Substitution)

• Purpose: Substitutes foo with bar in the string.
• Examples:
  • Basic Substitution:
    • Given: #{s/foo/bar/:foobar}
    • Result: barbar (replaces foo with bar).
  • Regex and Case-Insensitive:
    • Given: #{s/a(.)/\1x/i:abABab}
    • Result: bxBxbx (applies regex substitution).

8. #() (Shell Command Output)

• Purpose: Inserts the output of a shell command.
• Example:
  • Given: #(uptime)
  • Result: Inserts the system's uptime.

9. l: (Literal Interpretation)

• Purpose: Interprets a string literally without expansion.
• Example:
  • Given: #{l:#{?pane_in_mode,yes,no}}
  • Result: #{?pane_in_mode,yes,no} (treated as a literal string).

Use Cases and Additional Examples

• Dynamic Status Line
  • Using #{W:...} to create a custom status line that shows different formats for active and inactive windows.
• Custom Information Display
  • Using #(uptime) to display system uptime in the status bar.
• Conditional Formatting
  • Using #{?pane_in_mode,yes,no} with #{l:...} to display whether the current pane is in a specific mode.
• File Path Manipulation
  • Displaying just the directory or filename of a path in a pane title with #{b:...} and #{d:...}.
• Data Transformation
  • Using #{s/foo/bar/:} to dynamically change displayed text based on certain conditions or input.

Each of these formatting options allows for a high degree of customization in how information is displayed and managed within tmux, providing a powerful toolkit for enhancing your terminal experience.