bash: ./a.out Permission denied
bash: ./a.out Permission denied sh: ./a.out Permission denied Huh! Why the hell it is giving this error. It was working just fine previously. Reason 1: So, you may get this error sometime. I found this one when i tried to execute my executable file (a.out) on one of my friend's computer. When i checked it out thoroughly, I found out that normally in every executable file, there is a tab in properties of files. That tab is "Permissions". There is an option "Execute : Allow executing file as program". Just mark it true :-). a.out -> Right Click -> Properties -> Permissions -> Allow executing file as program Reason 2: Try running the file as root. You may not have permission to run the file, using sudo might work or change the permissions by using chmod . Note: This error might occur due to some other problems. I wrote this article in order to help those who have situations as described above. But please mention here if this kind of error is no