17

I am now under a directory with very long path. For future visiting it quicker, I would like to create a link to it.

I tried

ln -s . ~/mylink

~/mylink actually links to ~. So can I expand ~ into the obsolute pathname, and then give it to ln?

Gilles 'SO- stop being evil'
  • 829,060
Tim
  • 101,790

2 Answers2

25

A symlink actually stores the path you give literally, as a string¹. That means your link ~/mylink contains "." (one character). When you access the link, that path is interpreted relative to where the link is, rather than where you were when you made the link.

Instead, you can store the actual path you want in the link:

ln -s "$(pwd)" ~/mylink

using command substitution to put the output of pwd (the working directory name) into your command line. ln sees the full path and stores it into your symlink, which will then point to the right place.

¹ More or less.

Michael Homer
  • 76,565
9

You should use:

ln -s "$(cd . && pwd)" ~/mylink

or:

ln -s "$(pwd -P)" ~/mylink

to get the right result for current working directory. It can be changed while you was working in it as in this question.

Community
  • 1
cuonglm
  • 153,898
  • 1
    The first one will not necessarily help in all shells (see this answer). The OP likely wants to use $PWD (the path he used to get there), rather than $(pwd -P) (the canonical path to the current directory). If $PWD no longer points to the current directory, then there's no saying that $(pwd -P) will in the next minute either. – Stéphane Chazelas Aug 01 '14 at 09:48
  • @StéphaneChazelas: See this http://unix.stackexchange.com/questions/147693/how-do-pwd-and-determine-the-current-path-differently/147715#147715 – cuonglm Aug 01 '14 at 09:49
  • @StéphaneChazelas: You can see "$PWD" still have the old value if current direcory is moved. PWD only set when you cd or initialize by the shell. – cuonglm Aug 01 '14 at 10:22
  • But what I'm saying is that the OP is as likely to want the old $PWD than some absolute path to the current working directory and that in several shells (ksh93, ash, yash), as explained there calling cd is not guaranteed to make $PWD or the output of pwd a path to the current directory. You're trying to guard against something that is not likely to happen, but in the first solution, that's not necessarily effective, and in the second, that's changing the behaviour. – Stéphane Chazelas Aug 01 '14 at 10:35
  • I think the OP want the really value of curent working directory, as he also ask the question that . and pwd don't have the same value. Imagine that your are in /tmp/ttt. Now if someone try mv ../ttt ../tttt. PWD now still /tmp/ttt. Then you type ln -s "$(pwd)" ~/link. Then ls -l ~/link ==> broken symlink here. – cuonglm Aug 01 '14 at 11:21
  • 1
    If someone does the mv after you do ln, then you end up in the same situation. On the other hand, if he did cd /long/logical/path/to/some/directory, you don't want the link to point to /vg0/lv1/user2/app4 (the canonical path) as the link will point to the wrong place when /long/logical/path/to/some/directory points to somewhere else. – Stéphane Chazelas Aug 01 '14 at 11:36
  • Oh, I don't think about this situation, nested symlink. So you think what is the safer way to do this? – cuonglm Aug 01 '14 at 11:42
  • It all depends of context and what the OP wants to do. It's not that much about safety. A symlink can become broken at any moment, there's not much one can do about it. – Stéphane Chazelas Aug 01 '14 at 11:43
  • +1 for -P, the only thing that worked for me in a WD directory that was already a symlink. – Patrick M Jan 12 '16 at 16:30