3. paste

The paste command does the opposite of cut. Rather than extracting a column of text from a file, it adds one or more columns of text to a file.

To demonstrate how paste operates, we will perform some surgery on our distros.txt file to produce a chronological list of releases.

1. First let's sort distros by date:

   head distros.txt

   sort -k 3.7nbr -k 3.1nbr -k 3.4nbr \
       distros.txt > distros-by-date.txt

   head distros-by-date.txt

2. Next, let's use cut to extract the first two fields/columns from the file (the distro name and version):

   cut -f 1,2 distros-by-date.txt > distros-versions.txt

   head distros-versions.txt

   Let's also extract the release dates:

   cut -f 3 distros-by-date.txt > distros-dates.txt

   head distros-dates.txt

3. To complete the process, let's use paste to put the column of dates ahead of distro names and versions, thus creating a chronological list:

   paste distros-dates.txt distros-versions.txt \
       > distros-chronological.txt

   head distros-chronological.txt

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