This little sample shows how to copy your binaries to some location and set 'executable' attributes on them.
This can be used on a non-rooted phone, e.g. https://android.stackexchange.com/questions/53389/can-i-update-the-adb-shells-environment-variables
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To update the PATH variable inside a running adb shell you can use the expect command. This works on a non-rooted phone where you can't edit system files as suggested in the other answers.
Put the following script somewhere on the path of your development machine, for example in ~/bin/adb-shell-busybox:
#!/usr/bin/expect -- spawn adb shell expect "$" { sleep 0.1 send "export PATH=/data/data/burrows.apps.busybox/app_busybox/:$PATH\n" } interact You can also inject any other setup commands that you might need.