Linux – Making a duplicate of a path in Unix

directoryfilenameslinux

My Unix vocabulary is failing me. I have 5 billion images in /foo/live/images.

For the purposes of developing a new version of the app I'd like to make /foo/dev/images into a working path without making a copy of the images.

Is this a soft link? What's the right term? What's the command-line syntax to create the link?

Best Answer

Dead simple, it's just a symbolic link:

ln -s /foo/live/images /foo/dev/images

Just watch the directory permissions etc. To view the man page (all available options) for the ln command, enter the following at the prompt:

man ln

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Path Name – Dots in Path Name

The ../ is notation for "the parent directory" so, in the case you presented:

/usr/local/bin/../../etc/yarbu/conf/default

The system will resolve that as:

/usr/etc/yarbu/conf/default

It's the same as if you were in the directory /usr/local/bin and you then typed cd .. twice, you would now be in the /usr directory.

You can verify this yourself:

$ cd /usr/local/bin
$ pwd
/usr/local/bin
$ cd /usr/local/bin/../../../
$ pwd
/

Linux – program needs to be run as root by any user and can be located anywhere

With a caveat, the "right way" to allow a program to have root privileges and be run by any user, is to use setuid and setgid flags passed to chmod. This tutorial explain the process. You must be root to apply the setuid or setgid flags, and the program must be owned by root.

The caveat is that it is extremely insecure to allow a user to run a program with root privileges. Any exploit in the programs code can allow an ordinary user to obtain root privileges. Many linux exploits throughout the years have exploited a buggy setuid binary to obtain privilege escalation.

For informational and educational purposes only, here's how you do it:

chown root /usr/bin/myprogram
chmod u+s /usr/bin/myprogram

But, as others have said above, don't do this!

Best Answer

Related Solutions

Path Name – Dots in Path Name

Linux – program needs to be run as root by any user and can be located anywhere

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