[Bug]：The terminal returns a strange string

[ghost]

Command execution：
procs | procs

The terminal returns：
11;rgb:0e0e/1010/1919

Screenshot：

[dalance]

I fixed it, and released v0.12.0.

[Saduff]

I still have this issue using v0.12.0 over SSH. In my case, it happens with any procs command such as procs whatever. It's weird though, only seems to happen over SSH:

• localhost - no issue
• SSH into localhost - no issue
• SSH into server and execute procs whatever - issue is there
• same thing using "physical" terminal (tty1) via server's IPMI - no issue
• SSH into another server - issue is there

Not sure if it has something to do with my setup or not. Tried different terminal emulators (kitty, xfce terminal) and shells (zsh, bash), but same results.

[dalance]

@Saduff Could you provide the information about your SSH server / client and OS? I can't reproduce it.

[Saduff]

Client and server are both running Arch Linux. Client is running kernel 5.16.2, server is running 5.14.12. Both client and server are running OpenSSH 8.8p1, procs is installed from the Arch repo.

Thought it might have something to do with SSH multiplexing on the client-side as I have that turned on with this config:

ControlMaster auto
ControlPath /tmp/ssh_mux_%h_%p_%r
ControlPersist 10m

But disabling that made no difference. I also had X11 forwarding turned on with ForwardX11 yes, but disabling that made no difference either.

I could not reproduce it by SSHing into an archlinux docker container running locally. However, the issue is there when running procs inside the docker container on the server (over SSH). To be clear, the SSH connection is between my local machine and the server and then I simply ran procs inside the container.

[dalance]

How about more information about the docker container?
I tried archlinux:latest, but it can't be reproduced.

• Server side

$ docker run -it --rm --entrypoint /bin/bash archlinux:latest
# pacman -Sy openssh procs
# .. start sshd

• Client side

$ docker run -it --rm --entrypoint /bin/bash archlinux:latest
# ssh [server IP address]
# procs

[Saduff]

I tried the same way and could not reproduce it on my local machine, only on the remote server. On the server, the issue is there in the docker container as well when I run:

$ docker run --rm -it archlinux:latest
# pacman -Sy procs
# procs
^[]11;rgb:0000/0000/0000^[\ PID:▲ User │ TTY   CPU MEM CPU Time │ Command      
            │       [%] [%]          │              
 1     root │ pts/0 0.0 0.0 00:00:00 │ /usr/bin/bash
[root@a50d23103e27 /]# 11;rgb:0000/0000/0000

I found that the rgb string is printed to stderr, so I can suppress it like this and then everything is fine:

procs 2>/dev/null

What's weird is when I redirect it to a file, the file is empty:

# procs 2>test.txt
 PID:▲ User │ TTY   CPU MEM CPU Time │ Command      
            │       [%] [%]          │              
 1     root │ pts/0 0.0 0.0 00:00:00 │ /usr/bin/bash
# cat test.txt
# du test.txt
0 test.txt

I wish I had a way to reproduce it on my local machine, but I don't.

[dalance]

What's weird is when I redirect it to a file, the file is empty:

The 11;rgb:0000/0000/0000 is a return value of background color query to terminal.
procs suppress the query if stdout/stderr is piped or redirected, so the redirected file becomes to be empty.

[Saduff]

Okay, it definitely has something to do with my terminal emulator. I tried lots of different terminal emulators:

• Alacritty (TERM=alacritty) 🔴
• cool-retro-term (TERM=xterm) ✔️
• deepin-terminal (TERM=xterm-256color) ✔️
• Konsole (TERM=xterm-256color) 🔴
• kitty - my default (TERM=xterm-kitty) 🔴
• Liri Terminal (TERM=xterm-256color) ✔️
• QTerminal (TERM=xterm-256color) ✔️
• Terminology (TERM=xterm) 🔴
• urxvt (TERM=rxvt-unicode-256color) ✔️
• xterm (TERM=xterm) 🔴
• Xfce Terminal (TERM=xterm-256color) 🔴

✔️ denotes there's no issue (rgb string is not printed)
🔴 denotes that the rgb string is printed

None have the issue on my local machine, only when SSH'ed to the remote server.

[Saduff]

Okay, I found a way to reproduce it locally. It seems the issue has to do with network delay. The remote server is located far away so the latency is around 186 ms.

Steps to reproduce:

docker run --rm -it archlinux
# inside docker:
pacman -Sy openssh procs
ssh-keygen -A
echo 'PermitRootLogin yes' >> /etc/ssh/sshd_config
passwd # change root password
/bin/sshd

Now, on docker host:

ssh root@172.17.0.2 # change container IP if necessary
procs # should be fine

Now, let's introduce a 200 ms network delay by running this on the docker host:

tc qdisc add dev docker0 root netem delay 200ms # run as root or with sudo
# verify that delay was added:
ping 172.17.0.2
  PING 172.17.0.2 (172.17.0.2) 56(84) bytes of data.
  64 bytes from 172.17.0.2: icmp_seq=1 ttl=64 time=200 ms

Now run procs in the other window again and the rgb string should be displayed. Since I found that it depends on the terminal emulator as well, pick one from above with the red dot. I used kitty personally.

Finally, to remove the delay:

tc qdisc delete dev docker0 root netem delay 200ms # run as root or with sudo

And when running procs again in the other window, it should be fine again.

[dalance]

Thank you for your investigation.
procs waits 100ms until the query response.
So if there is 200ms network delay, procs will be timeout, after that the response will be displayed in the terminal.
But I can't increase the timeout because some terminals don't response the query.
I'll think another solution.

[dalance]

Could you try 83305be ?

[Saduff]

Seems to be fixed with that. Thanks for the quick fix and for this awesome project. 🙂