Linux – What’s the difference between “su” with and without hyphen

linuxsu

I'm quite new to Linux terminal and I'm not quite sure what the difference between su with a hyphen and su without a hyphen is, for example: su - username vs. su username.

I looked into the documentation but in there, this was not mentioned. Could someone please help me out?

Best Answer

The difference between "-" and "no hyphen" is that the latter keeps your existing environment (variables, etc); the former creates a new environment (with the settings of the actual user, not your own).

https://wiki.archlinux.org/index.php/Su

The hyphen has two effects:

1) switches from the current directory to the home directory of the new user (e.g., to /root in the case of the root user) by logging in as that user

2) changes the environmental variables to those of the new user as dictated by their ~/.bashrc. That is, if the first argument to su is a hyphen, the current directory and environment will be changed to what would be expected if the new user had actually logged on to a new session (rather than just taking over an existing session).

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This Ext2fsd FAQ states:

Q) What's a permanent mountpoint ?

A) Windows system's mount manager will automatically mount volumes and assign driver letters during booting. For xp and later systems, windows only create unique volume ids for all the recognized volume/partitions, such as FAT32, NTFS. The ext2/ext3 volumes could not be mounted by the windows mount manager.

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2, Using Windows MountMgr + Ext2Mgr This method provides automatic mounting when Ext2Mgr detects new disk is plugged and removal of driver letters after disk is removed. If you are heavily using removable disks, this is the best choice.

3, Using registry to store the driver letter as a DosDevice This method always works and it's better for fixed harddisks. Under some conditions, you need a reboot to see the driver letter in explorer.
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Thus probably the easiest way to solve your problem is to make a shortcuts to appropriate directories in your Windows Documents folder.

With linux you can add permanent bind mounts in fstab, for example:

/path_toyour_mddm_ount_point/Videos /path_to_you_home/Documents/Vdideo none bind

Best Answer

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