Pane.send_line
The text and then Enter, as one tmux invocation.
Source and package
- Qualified name
-
libtmux::Pane:: send _line - Namespace
- libtmux
- Declared in
Pane- Package
- libtmux-cxx
- Source
- include/libtmux/entities.hpp
- [[
C++ nodiscard attributeAsks the compiler to warn when a result is discarded. An explicit cast to void acknowledges that the result is intentionally ignored.]] expected<void, CommandFailure > send_line(std::string text) const;_view -
Description#
Running a command in a pane is two commands to tmux, and sending them separately costs two round trips and leaves a window where the line is typed and not submitted. This sends both in one batch, which tmux runs fail-fast, so a refused line is not followed by an Enter.
Empty text sends Enter alone, which is what submitting a blank line means.
send_text()refuses it instead: there, nothing would be sent.Examples#
Send input and capture confirmed output. Start a small shell reader with terminal echo disabled, wait for readiness, send one line, and capture its response. The two bounded waits prevent startup races and confirm output from the program. The final cat keeps the pane available for capture until cleanup. libtmux-cxx is not published to a package registry yet, so this builds it from its repository. Use Clang 18 or newer with libc++, CMake 3.25 or newer, Ninja, Git, and tmux 3.3a or newer on Linux. In an empty directory, fetch the documented library revision:
Terminal window $ git clone https://github.com/libtmux/libtmux-cxx.git libtmux-source && \git -C libtmux-source checkout 542fdc204ff3cfa56f5484327cda0c69bad2307dBuild and install the C++23 library and its public testing component into this directory:
Terminal window $ cmake -S libtmux-source -B libtmux-build -G Ninja \-DCMAKE_TOOLCHAIN_FILE="$PWD/libtmux-source/cmake/toolchains/clang-libcxx.cmake" \-DCMAKE_C_COMPILER=clang \-DCMAKE_CXX_COMPILER=clang++ \-DCMAKE_BUILD_TYPE=Release \-DLIBTMUX_BUILD_TESTS=OFF \-DLIBTMUX_BUILD_EXAMPLES=OFF \-DLIBTMUX_BUILD_TESTING_LIBRARY=ON && \cmake --build libtmux-build --parallel 2 && \cmake --install libtmux-build --prefix "$PWD/libtmux-prefix"Save this complete consumer project as
CMakeLists.txt: View sourcecmake_minimum_required(VERSION 3.25)project(libtmux_api_example LANGUAGES CXX)find_package(libtmux REQUIRED COMPONENTS testing)add_executable(api_example main.cpp)target_link_libraries(api_example PRIVATE libtmux::libtmux libtmux::testing)Save this complete program as
main.cpp.ScopedTmuxServerowns a private daemon and stops it when the program exits. Ordinary applications useServerfor their own socket; these examples use the fixture until setup moves to ordinary server objects. View source#include <algorithm>#include <chrono>#include <cstdio>#include <ranges>#include <libtmux/libtmux.hpp>#include <libtmux/testing/scoped_server.hpp>int main() {// The fixture owns this private server and cleans it up on every return path.auto fixture = libtmux::test::ScopedTmuxServer::start({.session_name = "api",.socket_namespace = libtmux::test::SocketNamespace::consumer("api"),});if (!fixture.has_value()) {std::fprintf(stderr, "%s\n", fixture.error().c_str());return 1;}auto server = libtmux::Server::at_socket_path(fixture->socket_path());if (!server.has_value()) {std::fprintf(stderr, "%s\n", server.error().diagnostic.c_str());return 1;}const auto sessions = server->sessions();if (!sessions.has_value()) {std::fprintf(stderr, "%s\n", sessions.error().diagnostic.c_str());return 1;}if (sessions->size() != 1) {std::fputs("expected one session\n", stderr);return 1;}const auto window = sessions->front().new_window(libtmux::NewWindowOptions{.name = "reader",.shell_command = R"(exec sh -c 'stty -echoprintf "ready\n"IFS= read -r lineprintf "got:%s\n" "$line"exec cat >/dev/null')",});if (!window.has_value()) {std::fprintf(stderr, "%s\n", window.error().diagnostic.c_str());return 1;}const auto pane = window->active_pane();if (!pane.has_value()) {std::fprintf(stderr, "%s\n", pane.error().diagnostic.c_str());return 1;}const auto ready = pane->wait_for_text("ready", {.timeout = std::chrono::seconds{5}});if (!ready.has_value()) {std::fprintf(stderr, "%s\n", ready.error().diagnostic.c_str());return 1;}if (!ready->matched) {std::fputs("reader did not become ready\n", stderr);return 1;}const auto text = pane->send_text("hello ");if (!text.has_value()) {std::fprintf(stderr, "%s\n", text.error().diagnostic.c_str());return 1;}const auto line = pane->send_line("C++");if (!line.has_value()) {std::fprintf(stderr, "%s\n", line.error().diagnostic.c_str());return 1;}const auto answered =pane->wait_for_text("got:hello C++", {.timeout = std::chrono::seconds{5}});if (!answered.has_value()) {std::fprintf(stderr, "%s\n", answered.error().diagnostic.c_str());return 1;}if (!answered->matched) {std::fputs("reader did not confirm the input\n", stderr);return 1;}const auto captured = pane->capture();if (!captured.has_value()) {std::fprintf(stderr, "%s\n", captured.error().diagnostic.c_str());return 1;}// The captured string outlives the line views returned by capture_lines.const auto lines = libtmux::capture_lines(*captured);if (std::ranges::find(lines, "got:hello C++") == std::ranges::end(lines)) {std::fputs("captured output does not contain the response\n", stderr);return 1;}std::puts("got:hello C++");return 0;}Build against the installed library and run the saved program. An operation error produces a failing exit status:
Terminal window $ cmake -S . -B build -G Ninja \-DCMAKE_PREFIX_PATH="$PWD/libtmux-prefix" \-DCMAKE_CXX_COMPILER=clang++ \-DCMAKE_CXX_FLAGS=-stdlib=libc++ && \cmake --build build --parallel 2 && \./build/api_exampleExpected output:
got:hello C++- Parameters
tmux command#
The tmux commands behind send_line.
tmux C API#
The C declarations in tmux that implement these commands.
Guides#
Pages that discuss send_line.