Working on a script for linscripts project (something I am working on my spare time), I encountered the following issue: I could not update a file info (such as a simple setting value) on a single line. I will explain in details:

I wanted to, by script, update a single value on a configuration file called apport, to enable crash reports on Ubuntu.
It is basically simple to do that such as:

    sed -e 's/enabled\=0/enabled\=1/' /etc/default/apport

However, the command below does not work:

    sed -e 's/enabled\=0/enabled\=1/' /etc/default/apport > /etc/default/apport

or worse, it removes all contents from the original file (do not try to do this!). So it means (I did not know) that stdin a file to a command and using the stdout directly does not work. Ok, you could do a temporary file and rename it back, of course, but I have found a more elegant solution in terms of scripting: to open a file for read/write using file descriptors:


Nice!

References

    [1] http://tldp.org/LDP/abs/html/io-redirection.html