What is an alternative to a BAT file on Mac?
Being pretty unfamiliar with batch files, I'm not sure of the functionality available, but there are two main scripting methods on OS X which are similar:


AppleScript

AppleScript is a scripting language which lets you control OS X and many applications.

AppleScripts are generally easy to understand and write whilst providing a lot of advanced functionality. Here is an AppleScript which counts the files in the Applications folder:

tell application "Finder"
    if folder "Applications" of startup disk exists then
        return count files in folder "Applications" of startup disk
    else
        return 0
    end if
end tell


For more information about AppleScript, see:


https://developer.apple.com/library/mac/documentation/applescript/Conceptual/AppleScriptX/AppleScriptX.html

Shell script

A shell script is a script for a Unix shell.

The equivalent shell script to the above AppleScript is the following:

if [ -d "/Applications/" ]; then
    ls -1 "/Applications/" | wc -l
fi


As you're probably going to use bash, this is a good guide to get you started:


http://www.tldp.org/LDP/abs/html/