Proper executable detection (looks for #! or ELF at the beginning of the file)

README.md

@@ -5,9 +5,6 @@ I'm trying to make it work well with [AppImages](http://appimage.org/).
 # Why?
 I know that Linux only has about 2% desktop usage and I know that the traditional way to install apps isn't portable, but over the past year or so I've started to put linux apps on my flash drive (AppImage is a great example of a portable solution to linux apps. Also a lot of DRM-free games can be run portably), but there was no easy way to organize my linux apps, so I created one. I personally have used the PortableApps.com launcher for years now and I love how properly formated the apps are, which allows me to grab info about the app easily.  
 
-# Why script files?
-In general linux executable files have no extensions and can be a pain when trying to figure out what is executable and what isn't. I figured script files are easy to detect and allow a large amount of flexibility for me (and others who want to make apps work with this launcher). See below for .AppImage support (Get AppImages from [here](https://bintray.com/probono/AppImages))
-
 # Why Go?
 Because I like Go :) Also the way it includes all it needs into one friendly executable.
 
@@ -20,15 +17,14 @@ The first place the program looks for an app's icon and info is in the /App/AppI
 # common.sh
 common.sh is run before any program so you can set environment variables (such as HOME). common.sh should be in PortableApps/LinuxPACom folder. Paths should be made relitive to where LinuxPA is.
 
-# AppImage support
-It will now launch .AppImage files! If a .sh script and an .AppImage executable are both in a directory, the .sh script takes precedence. You can get AppImages from [here](https://bintray.com/probono/AppImages).
+# Executable search
+For a given app, it tried to look for script files (looks for the file to start with `#!`) and then looks for standard executable files (looks for the file to start with `ELF`)
 
 # Screenshots
-![LinuxPA](https://lh3.googleusercontent.com/hdMfnnqj7jgsIAxzOMq3RD6iBlP3EVpqmH7SgowgAbidm6TncmksHlScV4OUkw4aOwG_OKSR1ukHRSY0kEk3rLjh8BEI60ZZO6sZp45g2qSanlYcq4-moDlRnbZOtur88K6sSWZRKXfRZ9ItDahDAdQLz5By_nf_aA4NZjn0d2XS4pnfhIGOPXZ8iFKgNfKHzWicJLlLw0nfXuUSAf60btbNlRLF7N0LEPH0INb0HD-f9w1W99NVNT5ooE18fOLlVks-ySHtxI9bqhNqfMC4kVB1Zt843KPxQQ_Slb0D_KnW58f2ARtYZyttWvXWOF2QhFeSzy8vI_lMVpnbtThcov1TZDZpPhjkiEF4hMb75zez-wpJ5DaJNvUTUcbn7wrj55UN6GgoZK7N_zn8kVhwPhQEEomLyCO9dtO9x5R1rhKYdTukvrupodhZRzI4KE9akqaMHLk3FC8A54PDnQvzBBDcxODxjxbyPYF50K55n26zoq6DXeJqbLAiDqqkaoCO74OXHyUQJbycVaG2uXsYRQ-0HcAuvEWj9XdeqsKj9qwtQuOOTZpp5JTu-0uRnLjML5503fhTjJS8AkWyav7zguXKaMq-QpRiywWKEPSSB14RP4Xy=w500-h534-no)
+Photos are found [Here](https://goo.gl/photos/VtBUL6DyZTMidj5n6)
 
 # TODO (Might be in order)
-1. MAKE IT BETTER  
-1. Improve linux executable detection (A.K.A. a pain in the butt) (I'm currently thinking of checking each file to see if the file starts out with #! or ELF)  
+1. MAKE IT BETTER   
 1. Launching of .exe files via wine (wine will have to be installed on the host system, unless there is some portable wine, I may have found one)  
 1. Add settings menu  
 1. Add updater for .AppImage files   

main.go

@@ -4,6 +4,7 @@ import (
 	"bufio"
 	"os"
 	"path"
+	"reflect"
 	"sort"
 	"strings"
 
@@ -79,18 +80,40 @@ func processApp(fi *os.File) (out prtap) {
 	if out.cat == "" {
 		out.cat = "other"
 	}
+	//executable detection
+	wd, _ := os.Getwd()
+	var rdr *bufio.Reader
 	for _, v := range fis {
-		if !v.IsDir() && strings.HasSuffix(strings.ToLower(v.Name()), ".sh") {
-			//do os check here for possible cross platform support
-			out.ex = fi.Name() + "/" + v.Name()
-			return
+		fil, err := os.Open(wd + "/" + fi.Name() + "/" + v.Name())
+		if err == nil {
+			stat, _ := fil.Stat()
+			if !stat.IsDir() {
+				rdr = bufio.NewReader(fil)
+				shebang := []byte{'#', '!'}
+				two := make([]byte, 2)
+				rdr.Read(two)
+				if reflect.DeepEqual(shebang, two) {
+					out.ex = wd + "/" + fi.Name() + "/" + v.Name()
+					rdr.Reset(fil)
+					return
+				}
+			}
 		}
 	}
 	for _, v := range fis {
-		if !v.IsDir() && strings.HasSuffix(strings.ToLower(v.Name()), ".appimage") {
-			//do os check here for possible cross platform support
-			out.ex = fi.Name() + "/" + v.Name()
-			return
+		fil, err := os.Open(wd + "/" + fi.Name() + "/" + v.Name())
+		if err == nil {
+			stat, _ := fil.Stat()
+			if !stat.IsDir() {
+				rdr = bufio.NewReader(fil)
+				thr := make([]byte, 4)
+				rdr.Read(thr)
+				if strings.Contains(string(thr), "ELF") {
+					out.ex = wd + "/" + fi.Name() + "/" + v.Name()
+					rdr.Reset(fil)
+					return
+				}
+			}
 		}
 	}
 	return prtap{}