Shell Programming and Scripting

the following command removes the first two characters of the first column, how can I change it to to remove the first two characters of the second column?
sed 's/^..//' file1.txt > file2.txt
Thanks
Joseph

No, the above removes 2 chars from the beginning of a line.
what is a 'column' and does it have to be 'sed'?

Hi
my file has two columns:
GAII_4:6:100:548:645/1 GTACACAACCCCCCCCCCCCACCCCACCCCCCCCCCCCCC
GAII_4:6:100:1:1242/1 GTCCTGCCCCTCCCCCTNNNNNNNTCTTTTNCCTCCTCCT
GAII_4:6:100:444:504/1 GTAACACACACCCTGATACTCCCCCCTCCACAACCGCTCT

I want to remove GT from the second column to get:
GAII_4:6:100:548:645/1 ACACAACCCCCCCCCCCCACCCCACCCCCCCCCCCCCC
GAII_4:6:100:1:1242/1 CCTGCCCCTCCCCCTNNNNNNNTCTTTTNCCTCCTCCT
GAII_4:6:100:444:504/1 AACACACACCCTGATACTCCCCCCTCCACAACCGCTCT

the function sed 's/^..//' file1.txt > file2.txt removes GA from the first column:
I_4:6:100:548:645/1 GTACACAACCCCCCCCCCCCACCCCACCCCCCCCCCCCCC
II_4:6:100:1:1242/1 GTCCTGCCCCTCCCCCTNNNNNNNTCTTTTNCCTCCTCCT
II_4:6:100:444:504/1 GTAACACACACCCTGATACTCCCCCCTCCACAACCGCTCT

Thanks

Code:

echo '123 4567' | sed 's/^\([^ ]* *\)..\(.*\)/\1\2/'
echo '123 4567' | awk '$2=substr($2,3)'

The second one worked.
Thank you so much