How to set an alias inside a bash shell script so that is it visible from the outside?
bash
Solution
`./script.sh` will be executed in a sub-shell and the changes made apply only the to sub-shell. Once the command terminates, the sub-shell goes and so do the changes.
sourcing the file using `. ./script.sh` or `source ./script.sh` will read and execute commands from the file-name argument in the current shell context, that is when a script is run using `source` it runs within the existing shell, any variables created or modified by the script will remain available after the script completes.
Problem
OSX: This works from the command line: ``` alias ruby="/opt/local/bin/ruby1.9" ``` but in side a shell script, it has no effect. I want to write a script that will switch between ruby 1.8 and ruby 1.9, so this needs to be a script - not in my profile. It appears "source script.sh" works, but "./script.sh". Why is this? How can I replicate this in my script?