I've two user accounts in my mac, One for me and other for my friend. When friend is using the MacBook and he needs some file from me, for that I've to login into my account and share the file by file sharing or USB data traveller. It takes time. What I want is, when my friend needs some file from my account, I should just double click on a folder in finder within my account under Users and finder ask my login id and password and grant me access on entering right password. How can I do so?
There are several options:
First, set up a shared folder on your account (or both if you need both way) so that every file you'll copy there will be visible from your friend account. You already have a public folder which can accomplish this. Next, you can enable fast user switch from Preferences > Users & Groups > Login Options. Doing so, you'll have login controls in the right side of the menu bar. You just need to login, copy the files in the public folder and logout.
Even faster, open the Terminal (Applications > Utility > Terminal), and type
it will ask for password. Enter it, and you will be logged on the shell with your account. From here, browse the folders and find the files you need (cd foldername to enter a folder, cp filesource filedestination to copy). Then logout with exit. Example:
Mac:~ Jack$ su epistrephein Password: bash-3.2$ cd Downloads bash-3.2$ cp picture6.jpg ~/Public/picture6.jpg bash-3.2$ exit Mac:~ Jack$