[Linux] Terminal Messaging via netcat - PC & Phone Over LAN
Send messages between your phone and PC like a hacker - with netcat & bash.
So, with SFTP, we can easily transfer files from phone to PC-fast and smooth.
But what if I just wanna send a quick text to my PC instead? Like… can I shoot a message straight to the terminal from my phone?
And that got me thinking-
How do hackers talk to each other through terminals, like in those classic hacker movies? You know, black screens… glowing green letters… mysterious chats flying across the command line…
Well, that’s exactly what we’re gonna talk about today. (I use 🐧 Pop!OS, but this works on any Linux distro.)
🧠 Netcat-based Terminal Messaging (No Permission B.S.)
First things first-make sure you can use Termius (or any other SSH app) on your phone to connect to your PC.
Then we can start the magic work:
🟢 Step 1 (on PC)
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nc -l -p 8888
🟢 Step 2 (on Phone)
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nc 192.168.1.2 8888
⬆️ Change 192.168.1.2 to your PC private ip.
Once the connection is established:
- One device listens (
nc -l -p 8888) - The other connects (
nc IP PORT) - Then? BOTH CAN TYPE in the same session 🫠💬
Now they’re 💞 bound 💞 in a full-duplex socket stream. You can:
- 📝 Type from PC - appears on Phone
- 📱 Type from Phone - appears on PC
Same session, no need for separate reverse flow.
This only works when Netcat on both ends supports full-duplex. Full-Duplex Ethernet = Two-Way Street, all modern routers support it.
Some older nc builds were single-direction only, gotta use two lanes for back-and-forth. 👇
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A: nc -l -p 1234
B: nc A_IP 1234
---
B: nc -l -p 5678
A: nc B_IP 5678
Scripts
So let’s organize all these features in to sh scripts:
| Feature | Description |
|---|---|
| 🌈 Colors | “Phone” = Magenta, “PC” = Blue |
| 📝 Logging | Saved to ~/Documents/Chat/chat_shared.log |
| ♾️ Infinite loop | Keeps listening / sending forever |
| 💬 Beautiful UX | Human-readable, timestamped, stylized messages |
💻 pc-chat.sh
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#!/bin/bash
LOG="$HOME/Documents/Chat/chat_shared.log"
mkdir -p "$(dirname "$LOG")"
while true; do
nc -l -p 8888 | while IFS= read -r line; do
msg="[$(date)] \033[1;35mPhone:\033[0m $line"
echo -e "$msg" | tee -a "$LOG"
done
done
📱 phone-chat.sh
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#!/bin/bash
LOG="$HOME/Documents/Chat/chat_shared.log"
mkdir -p "$(dirname "$LOG")"
while true; do
nc <PC_IP> 8888 | while IFS= read -r line; do
msg="[$(date)] \033[1;34mPC:\033[0m $line"
echo -e "$msg" | tee -a "$LOG"
done
done
- 😿 If
8888not a valid port for you, try change it, check What Port Range Should You Use. - 🔧 Replace
<PC_IP>with your actual private IP (e.g.,192.168.1.2) - 📝 The default log path is
~/Documents/Chat/chat_shared.log- feel free to change that
💌 Now Both Devices Will Log To:
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~/Documents/Chat/chat_shared.log
Here’s a sneak peek of what our terminal love looks like when Netcat is purring and TCP’s flowing hot: (yes… we timestamp everything) 😼
🧪 Quick Troubleshoot Checklist
If you’ve used this before and it suddenly breaks, try these steps to see if they help:
✅ 1. Is your PC Still Listening?
On PC, try in a fresh terminal:
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nc -l -p 8888
Then from the same PC terminal, in another tab:
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echo "test" | nc 127.0.0.1 8888
🧪 If this doesn’t work locally,
ncis dead or the port is stuck. 💣 Kill any stuckncprocesses:
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ps aux | grep nc
kill -9 <pid>
✅ 2. Confirm IPs Are Still Valid
PC:
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ip a | grep 192
→ You should see your private ip like 192.168.1.2
✅ 3. Can Phone Still Ping PC?
On Phone (via Termius or app):
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ping <PC_IP>
✅ = network is fine ❌ = something wrong with Wi-Fi, gateway, or router
🧠 If IPs changed (e.g. DHCP refresh), they may no longer match
✅ 4. Try Nmap from PC:
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nmap -Pn <PHONE_IP>
Check if any port shows up. If not, maybe your phone reconnected to a guest Wi-Fi, VPN, or hotspot.
✅ 5. Use netstat to Check Listeners
On PC:
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sudo netstat -tulnp | grep 8888
If you don’t see:
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tcp 0 0 0.0.0.0:8888 0.0.0.0:* LISTEN
Then PC isn’t listening on port 8888 anymore.
✅ 6. Try Alternate Port (e.g., 9999)
Sometimes the port gets “sticky.” Try:
PC:
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nc -l -p 9999
Phone:
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nc <PC_IP> 9999
🛠️ BONUS - Wipe Netcat Stuck Port
Sometimes a crashed nc process holds the port hostage. Run on PC:
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sudo fuser -k 8888/tcp
Then try again.
👀 If You Still Need a Reset:
Reboot both devices’ Wi-Fi (or even full reboot). Then try simple test again:
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# On PC
nc -l -p 8888
# On Phone
nc <PC_IP> 8888
Type anything - you should see it instantly.
TL;DR: Try This First
Kill all stuck nc:
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pkill nc
Try:
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nc -l -p 9999 # On PC nc <PC_IP> 9999 # On Phone
💥 Why Did Port Like 8888 Break?
Possible reasons:
| Reason | Explanation |
|---|---|
🔒 Leftover nc process | A stuck background listener was still holding 8888 hostage |
| ❌ Unclean disconnects | When a session is broken forcefully, it can “linger” in OS memory |
| 🧱 System firewall / timeout | Some systems automatically block a port after a ton of reconnections |
💡 Even after the script exits, the port stays in TIME_WAIT state for a bit
1. 🔁 TIME_WAIT ghost state
Some OSes (especially Linux) treat previously-used ports as “sensitive” if many rapid connects/disconnects occurred. It’ll let nc bind, but TCP refuses new connections from another device due to linger settings.
Try checking with:
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sudo ss -tanp | grep 8888
2. 🔐 iptables or firewall weirdness
Something might have marked 8888 as “bad” after repeated scans or failed handshakes.
Check firewall rules:
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sudo iptables -L -n | grep 8888
You might see
DROPorREJECTrules.
3. 🧠 Some apps love port 8888
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> nmap -p 8888 192.168.1.2
Starting Nmap 7.80 ( https://nmap.org ) at 2025-05-17 21:44 AWST
Nmap scan report for PC (192.168.1.2)
Host is up (0.000034s latency).
PORT STATE SERVICE
8888/tcp closed sun-answerbook
Fun fact:
8888is commonly used by:- Jupyter Notebook
- Some HTTP proxies
- Sun’s
answerbookservice (weird label in nmap 😅)
Even if not running now, your OS might have network settings baked around it
🧠 What Port Range Should You Use?
| Range | Notes |
|---|---|
| 1024-49151 | ✅ Safe to use - unprivileged ports |
| >49152-65535 | 🟡 Dynamic / ephemeral - may be used by OS |
| <1024 | 🔴 Privileged - needs sudo to bind (don’t use for chat) |
✅ Best range: 1025-49151 e.g.,
1337,2025,5454,9999,42069… get creative 😉
💬 Final Thoughts
You don’t need Slack, Signal, or servers.
You just need two devices, netcat, and a love for the terminal
Whether you’re debugging your LAN, leaving secret logs, or flirting through the command line -
this is messaging in its rawest, sexiest form.
Now go slide that string over, and let your sockets talk 💗
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