CS 3330: Tip on safe removal

This page does not represent the most current semester of this course; it is present merely as an archive.

Once you rm something, it is gone; recovery is spotty in practice and not something we’ll be able to use.

An extra buffer, similar to most desktop OS’s recycling bin, can be created by changing rm to an alias that doesn’t actually delete but moves to a trashcan directory instead.

Create an alias. We’ll put this in a file called .bashrc, which is run each time you log into a bash terminal either in person or via ssh.

1. Edit $HOME/.bashrc in your favorite editor. It likely already exists and contains code; we’ll add our code after it.

2. Create a trashing function in .bashrc:

   function trash_put() {
       while [ "$#" -gt 0 ]
       do
           if [ -e "$1" ]
           then
               to_delete="$(readlink -f "$1")"
               del_path="$(dirname "$to_delete")"
               del_name="$(basename "$to_delete")"
               now=$(date +%Y%m%d$H%M%s)
               mkdir -p $HOME/.trash/$now"$del_path"
               mv "$to_delete" $HOME/.trash/$now"$del_path"
           else
               echo "Cannot trash \`$1' (not a file or directory)"
           fi
           shift
       done
   }

   That is written in a language called Bash. Very useful to learn, but not within the scope of this course.

3. Create an alias in .bashrc

   alias rm='trash_put'

Once you have done this, any bash terminal will move files instead of removing them when you type rm. You can find the deleted files in $HOME/.trash/date-of-deletion/original/absolute/path/to/file.