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in puTTy, what does the @ sign signify when it's right after a directory?

ex.

pdf/
public_html/
video@

It is a symbolic link, however on another server, the same symbolic link does not have an @ sign after it.

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migrated from stackoverflow.com Oct 8 '10 at 2:35

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PuTTY is just a terminal program, and has nothing to do with what it is connecting to. You are actually asking about the format of the ls command, which is run in a shell that you invoke with PuTTY. –  Ether Oct 8 '10 at 2:01
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3 Answers 3

It's the difference between:

$ ls

and

$ ls -F

but it's not putty.

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What does it signify? I understand that there are 2 types of symbolic links..hard and soft.. which I created the link using ls -s /source /dest but on the old server the same directory did not have a @ sign after it. –  Sherdog Oct 8 '10 at 1:04
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Read "man ls", the authoritative source of information about the ls command. It might mean that ls is an alias on one of your accounts but not the other. –  Paul Beckingham Oct 8 '10 at 1:06
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Type man ls to read about the meaning of the symbols given when you list files. @ means the file is a symbolic link.

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I know this was answered, but i'd like to add some detail and it's hard to give large explanations in a comment window.

The ls command takes the -F flag which decorates certain filetypes with trailing characters. Directories take a /, executables *, symlinks @. If you're typing ls on two machines, and looking at the same filesystem on both but seeing different things, i think you have an alias or a function for ls on one that doesn't match the other. On both machines type type ls and I bet you'll get different output on both machines.

Also, in your comment, you talk about hard links and symlinks. They are very different. A symlink is a pointer to a file or directory. It's very similar to a shortcut in Windows (though UNIX did it better than Windows, which copied it poorly). It can point anywhere; on this disk, on another disk. Even the thing it points to may or may not be there. If I have a symlink that points to a file/dir that doesn't exist, it's called a dangling symlink.

A hard link is the name for the file. Think of a file really of two parts. There's the data, the actual info you put in the file. Your text, song, whatever. Or nothing, for an empty file. Then think of the metadata, info about your file. What's it's name? What type of file is it (file, directory, fifo, symlink, etc), When did i last write to it, what are the file permissions? This metadata is the hard link. In UNIX, they don't have a one to one relationship from this name-and-other-stuff metadata to the actual file. I can create more of these links - different names, different locations, different permissions. This is what's called hard linking. The system always creates one of these hard links when you create a file, but hard-linking usually only refers when you manually create another one using ln. A hard link can only be on the same file system as the data is, another difference from symbolic links. Linux systems also don't let you create hard links to directories, since that can make loops in the directory structure and cause real problems (MacOSX relaxes this a bit, since it uses hard links to make Time Machine(tm) backups more invisible to the user).

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Hard links are to inodes, not directly to the data. The inode conatins the permission bits, the user and group owners, the timestamps, etc. and links to the data blocks. Each hard link to the same file thus shares the same set of permissions. The metadata is not the hard link. Each directory entry is a (hard) link; each link points to an inode (the metadata); the inode points to the data itself. –  Chris Johnsen Oct 8 '10 at 18:46
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