Ubuntu – Can’t make a file executable

I had the same problem on my 64-bit machine when I downloaded file for 32-bit platform. Unfortunately you don´t see any error message if you try to execute such a file.

Check your file type using file command e.g.:

32-bit

N56VZ:~$ file /opt/eclipse/eclipse
eclipse: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), 
dynamically linked (uses shared libs), for GNU/Linux 2.2.5, not stripped

64-bit

N56VZ:~$ file /opt/eclipse/eclipse
eclipse: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), 
dynamically linked (uses shared libs), for GNU/Linux 2.4.0, not stripped

The option, to make a file executable is only shown for programs that the file manager considers to be of an executable file type. Jar-files are not in that list, although on Ubuntu setting them executable allows you to run them (maybe this should be reported as a bug?). Depending on the settings used when compiling the kernel (or generally on other operating systems), setting jar files executable might not work, and I guess this is the reason why file managers don't consider them runnable.

So, your options are:

• Use the command line tool chmod to add the execute permission. (chmod +x <filename>)
• Don't care about execute permissions and just always run java -jar <filename>.
  • You can create a launcher icon that runs this command.
  • You can create a write a wrapper shell script that can then be set executable. Most java programs available in the Ubuntu repositories install such a wrapper to /usr/bin, while the jar files reside in /usr/share/java