Keyboard shortcuts

Press ← or → to navigate between chapters

Press S or / to search in the book

Press ? to show this help

Press Esc to hide this help

Docker Image

As a lower-cost alternative to the local installation, you may install and use the CLI app from the GitHub Container registry. To run the app in a Docker container, use a command like

docker run -i --rm --env COLOR=always \
  ghcr.io/slowli/term-transcript:master \
  print - < examples/rainbow.svg

Here, the COLOR env variable sets the coloring preference for the output, and the - arg for the print subcommand instructs reading from stdin.

Running exec and test subcommands from a Docker container is more tricky since normally this would require taking the entire environment for the executed commands into the container. In order to avoid this, you can establish a bidirectional channel with the host using nc, which is pre-installed in the Docker image:

docker run --rm -v /tmp/shell.sock:/tmp/shell.sock \
  ghcr.io/slowli/term-transcript:master \
  exec --shell nc --echoing --args=-U --args=/tmp/shell.sock 'ls -al'

Here, the complete shell command connects nc to the Unix domain socket at /tmp/shell.sock, which is mounted to the container using the -v option.

On the host side, connecting the bash shell to the socket could look like this:

mkfifo /tmp/shell.fifo
cat /tmp/shell.fifo | bash -i 2>&1 | nc -lU /tmp/shell.sock > /tmp/shell.fifo &

Here, /tmp/shell.fifo is a FIFO pipe used to exchange data between nc and bash. The drawback of this approach is that the shell executable would not run in a (pseudo-)terminal and thus could look differently (no coloring etc.). To connect a shell in a pseudo-terminal, you can use socat, changing the host command as follows:

socat UNIX-LISTEN:/tmp/shell.sock,fork EXEC:"bash -i",pty,setsid,ctty,stderr &

TCP sockets can be used instead of Unix sockets, but are not recommended if Unix sockets are available since they are less secure. Indeed, care should be taken that the host “server” is not bound to a publicly accessible IP address, which would create a remote execution backdoor to the host system. As usual, caveats apply; e.g., one can spawn the shell in another Docker container connecting it and the term-transcript container in a single Docker network. In this case, TCP sockets are secure and arguably easier to use given Docker built-in DNS resolution machinery.