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Create links with absolute paths in Linux

Mostafa — Sat, 16 Jan 2010 19:10:18 +0000

The default behaviour of the linking command (ln) is a little strange under certain circumstances. Since it creates the links using the literal value of the target, symbolic links created using relative path structures can often fail. Consider the following:

$ ln -s targetfile ../src/targetfile_link

Without a doubt, ‘targetfile_link’ will be a broken symlink since it links to a target that it assumes is in the same directory:

$ cd ../src && ls -l targetfile_link
lrwxrwxrwx 1 mafgani mafgani 5 2010-01-16 18:19 targetfile_link -> targetfile

This is quite unfortunate since it clearly clashes with the way that the linking mechanism should work intuitively.

The solution is to force ln into automatically appending the absolute path to the target files. This can be achieved by using a simple shell script that acts as a wrapper for the real linking command:

#!/bin/sh

# Step through the supplied arguments and append the absolute
# path to targets that exist
for ARG in $@
do
  if [ -e $ARG ]; then
    LNARGS="${LNARGS} ${PWD}/${ARG}";
  else
    LNARGS="${LNARGS} ${ARG}";
  fi
done

# Execute the actual link command with the modified args
exec /bin/ln ${LNARGS};

There are two known caveats:

The link is ‘sub-optimal’ if created from within the destination directory (the absolute path contains ‘../’s). It will still work however.
The links will always be absolute. If that is undesirable, save the script as ‘absln’ or something other than ‘ln’.

Using ‘absln’ instead of ‘ln’ in the previously described scenario now produces a working symlink:

$ absln -s targetfile ../src/targetfile_link
$ cd ../src/ && ls -l targetfile_link
lrwxrwxrwx 1 mafgani mafgani 16 2010-01-16 19:13 targetfile_link -> /tmp/files/targetfile

Console based MSN client

Mostafa — Fri, 04 Nov 2005 11:49:00 +0000

Earlier today I stumbled across a client for MSN Messenger that runs in a terminal! It’s called tmsnc.

The RPM had some dependencies that I could not solve so I decided to compile from source. Apart from a few minor issues, it looks great! There are some screenshots available here.

You might wonder why you need a text based MSN client; well, one can never have too many tools

Open files from a terminal

Mostafa — Wed, 05 Oct 2005 22:48:00 +0000

There’s lot that can be learned from the conversations on the fedora-list. Today I learnt of a nifty little tool called gnome-open. Basically you just type something like:

[darkknight@darkworld ~]$ gnome-open file.cpp

and voila! It figures out the default application (under GNOME) for the files of type *.cpp and opens the file using that default editor. I haven’t verified, but it seems that instead of a file an URL can also be specified. Mmm .. it definitely creates the possibility of writing portable scripts; at least on GNOME systems anyway