eval "translates" a value buried inside a variable, and then runs the command that was buried in there
exec starts another process - BUT - it exits the current process when you do this kind of thing
source
When you run a command in the shell - like another script or a command like ls -
the shell creates a subprocess (called child process). Any environment variable that got defined or changed down in the child is LOST FOREVER to the parent process.
However if you source a script (there are two ways) you force the script to run in the current process. That means environment variables in the script you ran are NOT LOST.
This User Gave Thanks to jim mcnamara For This Post:
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