This might be obvious, but I can't see it - bash gives me a "command not found" error. The executable is in ~/bin. My PATH includes this directory (in expanded form). If I specify the path, it executes. I have a number of executables in the directory, and the 3 most recently compiled will not execute unless the path is specified. Several others will execute without a problem - in spite of having the same permissions! What am I doing wrong?