Pipe into `adb shell`

Question

Why can I not pipe into adb shell?

[klm@kth ~]$ echo foo | adb shell cat
^C

The above command hangs on my 4.0.1 emulator, and I'm not seeing the expected foo output.

I presume it's because adb shell doesn't pipe its stdin into its child-process' stdout, and cat sits and waits forever. Has this really not been implemented in adb, or am I missing something?

Answer 1

Here's my solution. Put the following into the adb_shell.sh file and use it instead of adb shell:

#!/bin/bash

adb forward tcp:12345 tcp:12345
adb shell busybox nc -lp 12345 -e "$@" &
sleep 1s
exec nc -q 1 localhost 12345

This creates an nc listener which runs the specified command upon the connection, and then connects to it.

Answer 2

An alternate option may be to use adb port forwarding and netcat.

Set Android side to recieve:

busybox nc -lp 5555 > piped_file.txt

PC side, set forwarding and send:

adb forward tcp:4444 tcp:5555 # Anything sent to localhost 4444 will be forwarded to Android 5555
cat piped_file.txt | busybox nc localhost 4444 # Pipe through the port to Android

The PC netcat connects to the Android netcat through the forwarded port, and the piped_file.txt is delivered.

---

Additional Info
Combined with tar, you can copy entire directory structures onto your device.

busybox nc -lp 5555 | tar -x # Android side

adb forward tcp:4444 tcp:5555 # PC side
tar -c directory | busybox nc localhost 4444

Answer 3

This is correct. This functionality has not been implemented.

Update:

A lot of bugs have been fixed and new features implemented in adb since the time the original question had been posted. Including support for proper stdin handling by adb shell. So there is no need for the netcat workarounds anymore.