Here are few ways to exit all background apps running on your iPhone 4S , iPhone 4 , iPad , iPod Touch 4 which supports multi-tasking . The apps that run in the background or are suspended in the memory can be closed all at once with and without jailbreaking using the apps/tweaks listed below .
Process Killer : AppStore
Recently launched in AppStore , “Process Kill” lets you exit from unwanted apps running in the background freeing up used memory . This app is priced $0.99 and requires no jailbreaking . Runs on all multi-tasking enabled devices including iPhone 4S , iPhone 4 , iPad , iPod Touch 4 . Cons : The apps closes itself when “Close All” command is given . iTunes Link .
Kill Background : Jailbreak App
This is a free app available on Cydia and very handy tweak for closing all apps at once . Just launch the task-switcher by double pressing the home button and tap on the red skill icon at the bottom right hand corner a shown in the image above . Tap it and all apps are gone except for the one which you are using . When launched from homescreen , closes all apps . Download Instructions
RemoveBG SBSettings Addon : Jailbreak App
This is a SBSettings add-on tweak that lets you do the same as the app above . Read how to download and use this tweak here .