Add gsr-cli program that sends ipc commands to gpu-screen-recorder

gsr-cli sends a command to the ipc socket of a running GPU Screen
Recorder and exits with 0 when it replied with ok, printing the reason to
stderr when it didn't, which means the commands don't have to be sent
blindly like signals are. The status command checks if GPU Screen
Recorder is running by connecting to the socket without sending a
command, so it's also correct when a killed instance left the socket
behind.
The json helpers moved into src/json.c to be shared between the two
programs.

1 files changed, 3 insertions, 2 deletions

diff --git a/README.md b/README.md
index 089076e..1b7502d 100644
--- a/README.md
+++ b/README.md
@@ -140,8 +140,9 @@ To stop recording send SIGINT to gpu screen recorder. You can do this by running
 To pause/unpause recording send SIGUSR2 to gpu screen recorder. You can do this by running `pkill -SIGUSR2 -f "^gpu-screen-recorder"`. This is only applicable and useful when recording (not streaming nor replay).\
 There are more signals to control GPU Screen Recorder. Run `gpu-screen-recorder --help` to list them all (under `NOTES` section).\
 GPU Screen Recorder can also be controlled with json messages over a unix domain socket by launching it with the `-ipc` option, for example `-ipc "$XDG_RUNTIME_DIR/gsr.sock"`.
-This gives the same control as the signals, except that a replay can be saved with an arbitrary number of seconds, for example `echo '{"id":1,"name":"save-replay","data":30}' | socat - "UNIX-CONNECT:$XDG_RUNTIME_DIR/gsr.sock"`.
-See the `IPC` section in the man page (`man gpu-screen-recorder`) for the full protocol.
+This gives the same control as the signals, except that a replay can be saved with an arbitrary number of seconds and that you get a reply that says if the command succeeded.\
+The `gsr-cli` program sends these commands, for example `gsr-cli -ipc "$XDG_RUNTIME_DIR/gsr.sock" save-replay 30`. It can also check if GPU Screen Recorder is running with `gsr-cli -ipc "$XDG_RUNTIME_DIR/gsr.sock" status`.\
+See `man gsr-cli` for all commands and the `IPC` section in `man gpu-screen-recorder` for the protocol, if you want to talk to the socket directly instead of using `gsr-cli`.
 ## Simple way to run replay without gui
 Run the script `scripts/start-replay.sh` to start replay and then `scripts/save-replay.sh` to save a replay and `scripts/stop-replay.sh` to stop the replay. The videos are saved to `$HOME/Videos`.
 You can use these scripts to start replay at system startup if you add `scripts/start-replay.sh` to startup (this can be done differently depending on your desktop environment / window manager) and then go into