Termux Skill

Reference for managing an Android device running Termux as a server.

Key Facts

• Termux is a user-space app — not a real Linux. No systemd. No root required (but this device has Magisk root).
• Package manager: pkg or /data/data/com.termux/files/usr/bin/apt (full path needed in SSH sessions)
• All binaries live at: /data/data/com.termux/files/usr/bin/
• Home dir: /data/data/com.termux/files/home/ (aka ~)
• PREFIX: /data/data/com.termux/files/usr/
• Python: /data/data/com.termux/files/usr/bin/python3 (v3.14.6)
• Node.js: /data/data/com.termux/files/usr/bin/node (v24.14.1)

SSH Access (from CachyOS)

ssh -o ProxyCommand="cloudflared access ssh --hostname term.YOUR-DOMAIN.example" \
    -p 8022 <termux-user>@term.YOUR-DOMAIN.example
# Or via SSH config alias:
ssh s9

IMPORTANT: SSH sessions on Android/Termux have a limited PATH (/sbin /system/bin etc — NOT the Termux bin dir). Always use full paths in SSH commands:

# Wrong (in SSH):  python3 script.py
# Right (in SSH):  /data/data/com.termux/files/usr/bin/python3 script.py

Process Persistence — The Android Problem

Android kills orphaned processes aggressively. nohup and setsid launched from SSH DO NOT survive when the SSH session closes. This is the #1 gotcha.

What DOES survive:

1. Processes started from within the Termux app UI (they're under Termux's process tree)
2. termux-services (runit) services — the proper solution
3. Termux:Boot scripts — run on device boot inside Termux context

What does NOT survive SSH:

• nohup python3 script.py &
• setsid python3 script.py &
• Background & processes

Correct Way: termux-services (runit)

The right way to run persistent daemons. Uses runit (same as Void Linux/Artix).

# Install from within Termux app on the phone:
pkg install termux-services

# Create a service directory:
mkdir -p $PREFIX/var/service/sv/myservice
cat > $PREFIX/var/service/sv/myservice/run << 'EOF'
#!/data/data/com.termux/files/usr/bin/sh
exec /data/data/com.termux/files/usr/bin/python3 /path/to/script.py
EOF
chmod +x $PREFIX/var/service/sv/myservice/run

# Start it:
sv up myservice

# Enable auto-start when Termux opens:
sv-enable myservice

# Stop:
sv down myservice

# Status:
sv status myservice

Service files live at: $PREFIX/var/service/sv/ = /data/data/com.termux/files/usr/var/service/sv/

Termux:Boot

Auto-runs scripts when Android boots. Requires Termux:Boot app installed and launched once.

Boot scripts live at: ~/.termux/boot/

Correct boot script pattern (sourcing profile is critical for PATH):

#!/data/data/com.termux/files/usr/bin/sh
termux-wake-lock
. $PREFIX/etc/profile   # ← sets PATH, env vars
# start termux-services (if using runit):
source /data/data/com.termux/files/usr/etc/profile.d/start-services.sh

Or manually start things:

#!/data/data/com.termux/files/usr/bin/sh
termux-wake-lock
. $PREFIX/etc/profile
sshd
nohup filebrowser ... &

NOTE: sleep 15 before network-dependent services is recommended — WiFi takes 10-15s after boot.

Package Management

# From within Termux app (not SSH):
pkg update && pkg upgrade
pkg install tmux python nodejs openssh termux-services

# From SSH (full path):
/data/data/com.termux/files/usr/bin/apt install tmux -y
# But this requires Termux user context — may fail with "root disabled" from SSH

Example: persistent Python bot service

Generic pattern for keeping a Python service alive (works for any long-running script):

Start from the Termux app (NOT from SSH — SSH children die when session ends):

cd ~/mybot
nohup python3 mybot.py >> bot.log 2>&1 &

Better — make it a runit service:

# Run this FROM the Termux app on the phone:
mkdir -p $PREFIX/var/service/sv/mybot
cat > $PREFIX/var/service/sv/mybot/run << 'EOF'
#!/data/data/com.termux/files/usr/bin/sh
cd /data/data/com.termux/files/home/mybot
exec /data/data/com.termux/files/usr/bin/python3 mybot.py
EOF
chmod +x $PREFIX/var/service/sv/mybot/run
sv-enable mybot
sv up mybot

File Locations (Android/Termux)

What	Path
Bot script	~/kammo_bot/kammo_bot.py
Bot inbox	~/kammo_bot/inbox.json
Bot outbox	~/kammo_bot/outbox.json
Boot script	~/.termux/boot/start-nas.sh
runit services	$PREFIX/var/service/sv/
SSH authorized_keys	~/.ssh/authorized_keys
cloudflared binary	/data/local/tmp/cloudflared
Cloudflare wrapper	/data/local/tmp/run-cloudflared.sh

Common Gotchas

1. PATH in SSH is wrong — always use full /data/data/com.termux/files/usr/bin/ paths
2. Processes die after SSH — use runit (termux-services) or start from Termux app
3. pkg not found in SSH — it's at /data/data/com.termux/files/usr/bin/apt
4. ps aux doesn't work — Android ps is different, just use ps | grep name
5. SELinux enforcing — root can't access Termux app_data_file context paths. Use su u0_a123 -c when needed.
6. WiFi-only device — no SIM. All network access via WiFi. DNS might hiccup on cloudflared v2026.7.1+ (use v2026.3.0).
7. Boot persistence — Termux:Boot fires BOOT_COMPLETED but WiFi takes ~15s. Add sleep 15 before network services.
8. Python is at python3 not python in newer Termux builds.

Useful One-Liners (from CachyOS over SSH)

# Check what's running:
ssh s9 "ps | grep -E 'python|cloudflared|navidrome|filebrowser'"

# Tail bot log:
ssh s9 "tail -f ~/kammo_bot/bot.log"

# Restart bot (only works if started from Termux app context previously):
ssh s9 "pkill -f kammo_bot && nohup /data/data/com.termux/files/usr/bin/python3 ~/kammo_bot/kammo_bot.py >> ~/kammo_bot/bot.log 2>&1 &"

# Quick file transfer to the device:
scp -P 8022 -o ProxyCommand="cloudflared access ssh --hostname term.YOUR-DOMAIN.example" file.py <termux-user>@term.YOUR-DOMAIN.example:~/

Sources

• Official wiki: https://wiki.termux.com (bot-protected, use browser)
• termux-boot: https://github.com/termux/termux-boot
• termux-services guide: https://ivonblog.com/en-us/posts/termux-services/
• PocketClaw boot pattern: https://pocketclaw.dev/guides/termux-boot
• SSH bootstrap skill: https://github.com/Sunwood-ai-labs/android-termux-ssh-bootstrap-skill