Nvim_terminal_emulator

Nvim :help pages, generated from source using the tree-sitter-vimdoc parser.

Terminal emulator terminal-emulator

Nvim embeds a VT220/xterm terminal emulator based on libvterm. The terminal is presented as a special 'buftype', asynchronously updated as data is received from the connected program.

Terminal buffers behave like normal buffers, except:

With 'modifiable', lines can be edited but not deleted.

'scrollback' controls how many lines are kept.

Output is followed ("tailed") if cursor is on the last line.

'modified' is the default. You can set 'nomodified' to avoid a warning when closing the terminal buffer.

'bufhidden' defaults to "hide".

Start terminal-start

There are several ways to create a terminal buffer:

Run the :terminal command.

Call the nvim_open_term() or termopen() function.

Edit a "term://" buffer. Examples:

:edit term://bash
:vsplit term://top

Note: To open a "term://" buffer from an autocmd, the autocmd-nested modifier is required.

autocmd VimEnter * ++nested split term://sh

(This is only mentioned for reference; use :terminal instead.)

When the terminal starts, the buffer contents are updated and the buffer is named in the form of term://{cwd}//{pid}:{cmd}. This naming scheme is used by :mksession to restore a terminal buffer (by restarting the {cmd}).

The terminal environment is initialized as in jobstart-env.

Input terminal-input

To send input, enter Terminal-mode with i, I, a, A or :startinsert. In this mode all keys except <C-\> are sent to the underlying program. If <C-\> is pressed, the next key is sent unless it is <C-N> or <C-O>. Use <C-\><C-N> to return to normal mode. CTRL-\_CTRL-N Use <C-\><C-O> to execute one normal mode command and then return to terminal mode. t_CTRL-\_CTRL-O

Terminal-mode forces these local options:

'cursorlineopt' = number 'nocursorcolumn' 'scrolloff' = 0 'sidescrolloff' = 0

Terminal-mode has its own :tnoremap namespace for mappings, this can be used to automate any terminal interaction.

To map <Esc> to exit terminal-mode:

:tnoremap <Esc> <C-\><C-n>

To simulate i_CTRL-R in terminal-mode:

:tnoremap <expr> <C-R> '<C-\><C-N>"'.nr2char(getchar()).'pi'

To use ALT+{h,j,k,l} to navigate windows from any mode:

:tnoremap <A-h> <C-\><C-N><C-w>h
:tnoremap <A-j> <C-\><C-N><C-w>j
:tnoremap <A-k> <C-\><C-N><C-w>k
:tnoremap <A-l> <C-\><C-N><C-w>l
:inoremap <A-h> <C-\><C-N><C-w>h
:inoremap <A-j> <C-\><C-N><C-w>j
:inoremap <A-k> <C-\><C-N><C-w>k
:inoremap <A-l> <C-\><C-N><C-w>l
:nnoremap <A-h> <C-w>h
:nnoremap <A-j> <C-w>j
:nnoremap <A-k> <C-w>k
:nnoremap <A-l> <C-w>l

You can also create menus similar to terminal mode mappings, but you have to use :tlmenu instead of :tmenu.

Mouse input has the following behavior:

If the program has enabled mouse events, the corresponding events will be forwarded to the program.

If mouse events are disabled (the default), terminal focus will be lost and the event will be processed as in a normal buffer.

If another window is clicked, terminal focus will be lost and nvim will jump to the clicked window

If the mouse wheel is used while the mouse is positioned in another window, the terminal won't lose focus and the hovered window will be scrolled.

Configuration terminal-config

Options: 'modified', 'scrollback' Events: TermOpen, TermEnter, TermLeave, TermClose Highlight groups: hl-TermCursor, hl-TermCursorNC

Terminal sets local defaults for some options, which may differ from your global configuration.

'list' is disabled

'wrap' is disabled

You can change the defaults with a TermOpen autocommand:

au TermOpen * setlocal list

TERMINAL COLORS

The {g,b}:terminal_color_x variables control the terminal color palette, where x is the color index between 0 and 15 inclusive. The variables are read during TermOpen. The value must be a color name or hexadecimal string. Example:

let g:terminal_color_4 = '#ff0000'
let g:terminal_color_5 = 'green'

Only works for RGB UIs (see 'termguicolors'); for 256-color terminals the color index is just forwarded.

Editor highlighting (syntax-highlighting, highlight-groups, etc.) has higher precedence: it is applied after terminal colors are resolved.

Status Variables terminal-status

Terminal buffers maintain some buffer-local variables and options. The values are initialized before TermOpen, so you can use them in a local 'statusline'. Example:

:autocmd TermOpen * setlocal statusline=%{b:term_title}

b:term_title Terminal title (user-writable), typically displayed in the window title or tab title of a graphical terminal emulator. Terminal programs can set this by emitting an escape sequence.

'channel' Terminal PTY job-id. Can be used with chansend() to send input to the terminal.

The TermClose event gives the terminal job exit code in the v:event "status" field. For example, this autocmd closes terminal buffers if the job exited without error:

autocmd TermClose * if !v:event.status | exe 'bdelete! '..expand('<abuf>') | endif

Use jobwait() to check if the terminal job has finished:

let running = jobwait([&channel], 0)[0] == -1

============================================================================== :Termdebug plugin terminal-debug

The Terminal debugging plugin can be used to debug a program with gdb and view the source code in a Vim window. Since this is completely contained inside Vim this also works remotely over an ssh connection.

Starting

termdebug-starting Load the plugin with this command:

packadd termdebug

:Termdebug To start debugging use :Termdebug or :TermdebugCommand followed by the command name, for example:

:Termdebug vim

This opens two windows:

gdb window A terminal window in which "gdb vim" is executed. Here you can directly interact with gdb.

program window A terminal window for the executed program. When "run" is used in gdb the program I/O will happen in this window, so that it does not interfere with controlling gdb.

The current window is used to show the source code. When gdb pauses the source file location will be displayed, if possible. A sign is used to highlight the current position, using highlight group debugPC.

If the buffer in the current window is modified, another window will be opened to display the current gdb position.

Focus the terminal of the executed program to interact with it. This works the same as any command running in a terminal window.

When the debugger ends, typically by typing "quit" in the gdb window, the two opened windows are closed.

Only one debugger can be active at a time. :TermdebugCommand If you want to give specific commands to the command being debugged, you can use the :TermdebugCommand command followed by the command name and additional parameters.

:TermdebugCommand vim --clean -c ':set nu'

Both the :Termdebug and :TermdebugCommand support an optional "!" bang argument to start the command right away, without pausing at the gdb window (and cursor will be in the debugged window). For example:

:TermdebugCommand! vim --clean

To attach gdb to an already running executable or use a core file, pass extra arguments. E.g.:

:Termdebug vim core
:Termdebug vim 98343

If no argument is given, you'll end up in a gdb window, in which you need to specify which command to run using e.g. the gdb file command.

Example session

termdebug-example Start in the Vim "src" directory and build Vim:

% make

Start Vim:

% ./vim

Load the termdebug plugin and start debugging Vim:

:packadd termdebug
:Termdebug vim

You should now have three windows: source - where you started gdb - you can type gdb commands here program - the executed program will use this window

Put focus on the gdb window and type:

break ex_help
run

Vim will start running in the program window. Put focus there and type:

:help gui

Gdb will run into the ex_help breakpoint. The source window now shows the ex_cmds.c file. A red "1 " marker will appear in the signcolumn where the breakpoint was set. The line where the debugger stopped is highlighted. You can now step through the program. You will see the highlighting move as the debugger executes a line of source code.

Run ":Next" a few times until the for loop is highlighted. Put the cursor on the end of "eap->arg", then call ":Eval". You will see this displayed:

"eap->arg": 0x555555e68855 "gui"

This way you can inspect the value of local variables. You can also focus the gdb window and use a "print" command, e.g.:

print *eap

If mouse pointer movements are working, Vim will also show a balloon when the mouse rests on text that can be evaluated by gdb. You can also use the "K" mapping that will either use Nvim floating windows if available to show the results or print below the status bar.

Now go back to the source window and put the cursor on the first line after the for loop, then type:

:Break

You will see a "1" marker appear, this indicates the new breakpoint. Now run ":Cont" command and the code until the breakpoint will be executed.

You can type more advanced commands in the gdb window. For example, type:

watch curbuf

Now run ":Cont" (or type "cont" in the gdb window). Execution will now continue until the value of "curbuf" changes, which is in do_ecmd(). To remove this watchpoint again type in the gdb window:

delete 3

You can see the stack by typing in the gdb window:

where

Move through the stack frames, e.g. with:

frame 3

The source window will show the code, at the point where the call was made to a deeper level.

Stepping through code

termdebug-stepping Put focus on the gdb window to type commands there. Some common ones are:

CTRL-C interrupt the program

next execute the current line and stop at the next line

step execute the current line and stop at the next statement, entering functions

until execute until past the current cursor line or past a specified position or the current stack frame returns

finish execute until leaving the current function

where show the stack

frame N go to the Nth stack frame

continue continue execution

:Run :Arguments In the window showing the source code these commands can be used to control gdb: :Run [args] run the program with [args] or the previous arguments :Arguments {args} set arguments for the next :Run

:Break set a breakpoint at the current line; a sign will be displayed :Clear delete the breakpoint at the current line

:Step execute the gdb "step" command :Over execute the gdb "next" command (:Next is a Vim command) :Until execute the gdb "until" command :Finish execute the gdb "finish" command :Continue execute the gdb "continue" command :Stop interrupt the program

If gdb stops at a source line and there is no window currently showing the source code, a new window will be created for the source code. This also happens if the buffer in the source code window has been modified and can't be abandoned.

Gdb gives each breakpoint a number. In Vim the number shows up in the sign column, with a red background. You can use these gdb commands:

info break list breakpoints

delete N delete breakpoint N You can also use the :Clear command if the cursor is in the line with the breakpoint, or use the "Clear breakpoint" right-click menu entry.

Inspecting variables

termdebug-variables :Evaluate :Evaluate evaluate the expression under the cursor K same (see termdebug_map_K to disable) :Evaluate {expr} evaluate {expr} :'<,'>Evaluate evaluate the Visually selected text

This is similar to using "print" in the gdb window. You can usually shorten :Evaluate to :Ev.

Other commands

termdebug-commands :Gdb jump to the gdb window :Program jump to the window with the running program :Source jump to the window with the source code, create it if there isn't one :Asm jump to the window with the disassembly, create it if there isn't one

Events

termdebug-events Four autocommands can be used:

au User TermdebugStartPre  echomsg 'debugging starting'
au User TermdebugStartPost echomsg 'debugging started'
au User TermdebugStopPre   echomsg 'debugging stopping'
au User TermdebugStopPost  echomsg 'debugging stopped'

TermdebugStartPre TermdebugStartPre Before starting debugging. Not triggered if the debugger is already running or the debugger command cannot be executed. TermdebugStartPost TermdebugStartPost After debugging has initialized. If a "!" bang is passed to :Termdebug or :TermdebugCommand the event is triggered before running the provided command in gdb. TermdebugStopPre TermdebugStopPre Before debugging ends, when gdb is terminated, most likely after issuing a "quit" command in the gdb window. TermdebugStopPost TermdebugStopPost After debugging has ended, gdb-related windows are closed, debug buffers wiped out and the state before the debugging was restored.

Customizing

termdebug-customizing g:termdebug_config In the past several global variables were used for configuration. These are deprecated and using the g:termdebug_config dictionary is preferred. When g:termdebug_config exists the other global variables will NOT be used. The recommended way is to start with an empty dictionary:

let g:termdebug_config = {}

Then you can add entries to the dictionary as mentioned below. The deprecated global variable names are mentioned for completeness. If you are switching over to using g:termdebug_config you can find the old variable name and take over the value, then delete the deprecated variable.

Prompt mode

termdebug-prompt When on MS-Windows, gdb will run in a buffer with 'buftype' set to "prompt". This works slightly differently:

The gdb window will be in Insert mode while typing commands. Go to Normal mode with <Esc>, then you can move around in the buffer, copy/paste, etc. Go back to editing the gdb command with any command that starts Insert mode, such as a or i.

A separate :terminal window will be opened to run the debugged program in.

termdebug_use_prompt Prompt mode can be used with:

let g:termdebug_config['use_prompt'] = 1

If there is no g:termdebug_config you can use:

let g:termdebug_use_prompt = 1

termdebug_map_K The K key is normally mapped to :Evaluate. If you do not want this use:

let g:termdebug_config['map_K'] = 0

If there is no g:termdebug_config you can use:

let g:termdebug_map_K = 0

termdebug_disasm_window If you want the Asm window shown by default, set the flag to 1. the "disasm_window_height" entry can be used to set the window height:

let g:termdebug_config['disasm_window'] = 1
let g:termdebug_config['disasm_window_height'] = 15

If there is no g:termdebug_config you can use:

let g:termdebug_disasm_window = 15

Any value greater than 1 will set the Asm window height to that value.

Communication

termdebug-communication There is another, hidden, buffer, which is used for Vim to communicate with gdb. The buffer name is "gdb communication". Do not delete this buffer, it will break the debugger.

Gdb has some weird behavior, the plugin does its best to work around that. For example, after typing "continue" in the gdb window a CTRL-C can be used to interrupt the running program. But after using the MI command "-exec-continue" pressing CTRL-C does not interrupt. Therefore you will see "continue" being used for the :Continue command, instead of using the communication channel.

GDB command

g:termdebugger To change the name of the gdb command, set "debugger" entry in g:termdebug_config or the "g:termdebugger" variable before invoking :Termdebug:

let g:termdebug_config['command'] = "mygdb"

If there is no g:termdebug_config you can use:

let g:termdebugger = "mygdb"

If the command needs an argument use a List:

let g:termdebug_config['command'] = ['rr', 'replay', '--']

If there is no g:termdebug_config you can use:

let g:termdebugger = ['rr', 'replay', '--']

To not use Nvim floating windows for previewing variable evaluation, set the g:termdebug_useFloatingHover variable like this:

let g:termdebug_useFloatingHover = 0

If you are a mouse person, you can also define a mapping using your right click to one of the terminal command like evaluate the variable under the cursor:

nnoremap <RightMouse> :Evaluate<CR>

or set/unset a breakpoint:

nnoremap <RightMouse> :Break<CR>

Several arguments will be added to make gdb work well for the debugger. If you want to modify them, add a function to filter the argument list:

let g:termdebug_config['command_filter'] = MyDebugFilter

If you do not want the arguments to be added, but you do need to set the "pty", use a function to add the necessary arguments:

let g:termdebug_config['command_add_args'] = MyAddArguments

The function will be called with the list of arguments so far, and a second argument that is the name of the pty. gdb-version Only debuggers fully compatible with gdb will work. Vim uses the GDB/MI interface. The "new-ui" command requires gdb version 7.12 or later. if you get this error: Undefined command: "new-ui". Try "help".~ Then your gdb is too old.

Colors

hl-debugPC hl-debugBreakpoint The color of the signs can be adjusted with these highlight groups:

debugPC the current position

debugBreakpoint a breakpoint

The defaults are, when 'background' is "light": hi debugPC term=reverse ctermbg=lightblue guibg=lightblue hi debugBreakpoint term=reverse ctermbg=red guibg=red

When 'background' is "dark": hi debugPC term=reverse ctermbg=darkblue guibg=darkblue hi debugBreakpoint term=reverse ctermbg=red guibg=red

Shortcuts

termdebug_shortcuts You can define your own shortcuts (mappings) to control gdb, that can work in any window, using the TermDebugSendCommand() function. Example:

map ,w :call TermDebugSendCommand('where')<CR>

The argument is the gdb command.

Popup menu

termdebug_popup By default the Termdebug plugin sets 'mousemodel' to "popup_setpos" and adds these entries to the popup menu: Set breakpoint :Break Clear breakpoint :Clear Evaluate :Evaluate If you don't want this then disable it with:

let g:termdebug_config['popup'] = 0

If there is no g:termdebug_config you can use:

let g:termdebug_popup = 0

Vim window width

termdebug_wide To change the width of the Vim window when debugging starts and use a vertical split:

let g:termdebug_config['wide'] = 163

If there is no g:termdebug_config you can use:

let g:termdebug_wide = 163

This will set 'columns' to 163 when :Termdebug is used. The value is restored when quitting the debugger.

If the wide value is set and 'columns' is already a greater value, then a vertical split will be used without modifying 'columns'.

Set the wide value to 1 to use a vertical split without ever changing 'columns'. This is useful when the terminal can't be resized by Vim.