term2plain - Record an interactive terminal session, and convert it to plain text.

term2plain.bash

#! /usr/bin/env bash

# All my gist code is licensed under the MIT license.

# term2plain
# - Convert a text file containing terminal escape sequences to plain text.
# - This plain text is close to the visual result of running the file in a
#   terminal.
# - This is achieved by running the file in a virtual terminal (tmux) and
#   capturing it's buffer output.
# - For simple escape sequences like color, this might be overkill, but it's
#   useful for interactive programs which read user input, and the cursor 
#   move sequences must be interpreted to produce the final input.
# - Example:
#   $ interactive-program | tee output.txt # works for simple ones like 
#                                          # sqlite or gdb, not vim
#   $ term2plain output.txt
#   $ vim output.txt # see the plain-text output after escape sequences were
#                    # processed by a virtual terminal.

# Store the file path and the name for the tmux session
file_path="$1"
session_name="term2plain_session"
output="/tmp/term2plain_output.txt"

start_marker="#term2plain-start"
end_marker="#term2plain-end"

SLEEP_TIME=0.1 # adjust sleep as needed based on file size

# bail if tmux is not installed
if ! command -v tmux &> /dev/null; then
  echo "Error: tmux is not installed"
  exit 1
fi

# Create a new detached tmux session
tmux new-session -d -s "$session_name"

# Send the 'cat' command to the session
tmux send-keys -t "$session_name" "cat '$file_path'" ' \' C-m "$start_marker" C-m

# Wait a little to make sure 'cat' has finished
sleep $SLEEP_TIME

# type end marker
tmux send-keys -t "$session_name" "$end_marker" C-m

# Capture the pane output
tmux capture-pane -pS - -t "$session_name" >| "$output"

# Kill the tmux session
tmux kill-session -t "$session_name"

# remove everything before and after markers
sed -i -e '1,/'"${start_marker}"'/d' "$output"
sed -i -e '/'"${end_marker}"'/,$d' "$output"

# Print the captured output
cat "$output"

/usr/bin/rm "$output"