Use awk command line to combine columns
<p>I  want to use awk to combine columns starting from 4th column till the end of columns.</p>

<p>Input:</p>

<pre><code>1   682333  191.858 191517119   C   A   C   A   A   A   C   A   A   A   A   A
2   1862626 71.9275 56032940    A   C   C   C   A   A   A   C   A   C   A   A
3   11957134    155.78  150230950   B   B   B   B   A   B   A   B   A   B   A   B
4   2516482 51.2692 31496569    B   A   A   A   A   A   A   A   A   A   A   A
5   9378200 51.2798 31572927    A   A   B   B   B   A   A   A   A   A   B   A
6   2071534 52.1573 32824318    A   B   A   B   A   B   A   B   B   B   A   B
7   2074633 33.068  19035920    A   A   B   A   A   A   B   A   B   A   B   A
8   7856856 121.811 117540910   A   A   A   A   A   A   A   A   B   A   B   A
9   3741206 2.18574 2169864 A   A   A   A   A   A   A   A   A   A   A   A
10  4411364 12.5959 24191374    C   C   A   C   A   C   C   C   A   C   A   C
</code></pre>

<p>Output:</p>

<pre><code>1   682333  191.858 191517119   CA      CA      AA      CA      AA      AA
2   1862626 71.9275 56032940    AC      CC      AA      AC      AC      AA
3   11957134    155.78  150230950   BB      BB      AB      AB      AB      AB
4   2516482 51.2692 31496569    BA      AA      AA      AA      AA      AA
5   9378200 51.2798 31572927    AA      BB      BA      AA      AA      BA
6   2071534 52.1573 32824318    AB      AB      AB      AB      BB      AB
7   2074633 33.068  19035920    AA      BA      AA      BA      BA      BA
8   7856856 121.811 117540910   AA      AA      AA      AA      BA      BA
9   3741206 2.18574 2169864 AA      AA      AA      AA      AA      AA
10  4411364 12.5959 24191374    CC      AC      AC      CC      AC      AC
</code></pre>

<p>By the way, if there is any good website for an awk command tutorial, please recommend it here.</p>