Using tmux for Interactive Commands
Overview
Interactive CLI tools (vim, interactive git rebase, REPLs, etc.) cannot be controlled through standard bash because they require a real terminal. tmux provides detached sessions that can be controlled programmatically via
send-keys
and
capture-pane
.
When to Use
Use tmux when:
Running vim, nano, or other text editors programmatically
Controlling interactive REPLs (Python, Node, etc.)
Handling interactive git commands (
git rebase -i
,
git add -p
)
Working with full-screen terminal apps (htop, etc.)
Commands that require terminal control codes or readline
Don't use for:
Simple non-interactive commands (use regular Bash tool)
Commands that accept input via stdin redirection
One-shot commands that don't need interaction
Quick Reference
Task
Command
Start session
tmux new-session -d -s
This hangs because vim expects interactive terminal
bash -c "vim file.txt" After (Works)
Create detached tmux session
tmux new-session -d -s edit_session vim file.txt
Send commands (Enter, Escape are tmux key names)
tmux send-keys -t edit_session 'i' 'Hello World' Escape ':wq' Enter
Capture what's on screen
tmux capture-pane -t edit_session -p
Clean up
tmux kill-session -t edit_session Implementation Basic Workflow Create detached session with the interactive command Wait briefly for initialization (100-500ms depending on command) Send input using send-keys (can send special keys like Enter, Escape) Capture output using capture-pane -p to see current screen state Repeat steps 3-4 as needed Terminate session when done Special Keys Common tmux key names: Enter - Return/newline Escape - ESC key C-c - Ctrl+C C-x - Ctrl+X Up , Down , Left , Right - Arrow keys Space - Space bar BSpace - Backspace Working Directory Specify working directory when creating session: tmux new-session -d -s git_session -c /path/to/repo git rebase -i HEAD~3 Helper Wrapper For easier use, see /home/jesse/git/interactive-command/tmux-wrapper.sh :
Start session
/path/to/tmux-wrapper.sh start < session-name
< command
[ args .. . ]
Send input
/path/to/tmux-wrapper.sh send < session-name
'text' Enter
Capture current state
/path/to/tmux-wrapper.sh capture < session-name
Stop
/path/to/tmux-wrapper.sh stop < session-name
Common Patterns Python REPL tmux new-session -d -s python python3 -i tmux send-keys -t python 'import math' Enter tmux send-keys -t python 'print(math.pi)' Enter tmux capture-pane -t python -p
See output
tmux kill-session -t python Vim Editing tmux new-session -d -s vim vim /tmp/file.txt sleep 0.3
Wait for vim to start
tmux send-keys -t vim 'i' 'New content' Escape ':wq' Enter
File is now saved
Interactive Git Rebase tmux new-session -d -s rebase -c /repo/path git rebase -i HEAD~3 sleep 0.5 tmux capture-pane -t rebase -p
See rebase editor
Send commands to modify rebase instructions
tmux send-keys -t rebase 'Down' 'Home' 'squash' Escape tmux send-keys -t rebase ':wq' Enter Common Mistakes Not Waiting After Session Start Problem: Capturing immediately after new-session shows blank screen Fix: Add brief sleep (100-500ms) before first capture tmux new-session -d -s sess command sleep 0.3
Let command initialize
tmux capture-pane -t sess -p Forgetting Enter Key Problem: Commands typed but not executed Fix: Explicitly send Enter tmux send-keys -t sess 'print("hello")' Enter
Note: Enter is separate argument
Using Wrong Key Names Problem: tmux send-keys -t sess '\n' doesn't work Fix: Use tmux key names: Enter , not \n tmux send-keys -t sess 'text' Enter
✓
tmux send-keys -t sess 'text\n'
✗
Not Cleaning Up Sessions Problem: Orphaned tmux sessions accumulate Fix: Always kill sessions when done tmux kill-session -t session_name
Or check for existing: tmux has-session -t name 2>/dev/null
Real-World Impact Enables programmatic control of vim/nano for file editing Allows automation of interactive git workflows (rebase, add -p) Makes REPL-based testing/debugging possible Unblocks any tool that requires terminal interaction No need to build custom PTY management - tmux handles it all