handy script for injecting one-line cycript code in a process on your target device and exiting after execution.

cyexec

#!/bin/sh

# Usage: ./cyexec <process> <code>
#
# Example #1 (Locks device):
#
#     ./cyexec SpringBoard '[[SBUserAgent sharedUserAgent] lockAndDimDevice]'
#
# Example #2 (Shows an alert message):
#
#     ./cyexec SpringBoard '[[[[UIAlertView alloc] initWithTitle:@"OH HAI" message:@"This is a test message!" delegate:nil cancelButtonTitle:@"Got it" otherButtonTitles:nil] autorelease] show]'
#
# Useful to automate arbitrary code execution in your theos Makefile (before-install, after-install, etc)
#

process=$1
shift
echo $* > /tmp/die && cycript -p $process /tmp/die; rm /tmp/die