Unfortunately, I learned that there's is no way to invoke cd programmatically from a program, but I didn't get an explanation I could understand why this is not possible.
Can someone explain why you can't invoke cd from a program?
# eg. save mc
# cd mc # no '$' is necessary
if [ ! -f ~/.dirs ]; then # if doesn't exist, create it
touch ~/.dirs
fi
alias show='cat ~/.dirs'
save (){
command sed "/!$/d" ~/.dirs > ~/.dirs1; \mv ~/.dirs1 ~/.dirs; echo "$@"=\"`pwd`\" >> ~/.dirs; source ~/.dirs ;
source ~/.dirs # Initialization for the above 'save' facility: source the .sdirs file
}
source ~/.dirs # Initialization for the above 'save' facility: source the .sdirs file
shopt -s cdable_vars # set the bash option so that no '$' is required when using the above facility
Also, you can just type `show` and any point and it'll tell you what you've saved and where.
The nicest thing is that this persists with new logins (the only drawback is that other shells that are running don't get the update automatically).
You can't change another process's internal state without sending a message that the other process can choose to interpret (or by hacking the memory that the process is using)
As far as I know, you will need to provide the user with an alias or a function or something that can put in their .bashrc or something, and there is no other way to do it. (Anything that could would constitute a violation of the UNIX process model.)