Calling a substring from another file

Shell Programming and Scripting
1

I have two files:

One is a list of numbers:

1
5
6
7
10

The second is a very long string

abcdefghijklmno......1234567890

I'd like to print a new file with a 5 character substring that starts at each the positions listed in the 1st file:

such as:

abcde
efghi
fghij
ghijk
jklmno

I've attempted a few While and If loops but can't seem to get the syntax correct.

Thank you.

2

Next time post your code, like that we can see where exactly are you stuck?
Here is the solution using awk.

awk '
      NR==FNR{
             a[NR]=$0
             next
             }
             {
              for(i=1;i<NR;i++) 
                  print substr($0,a,5)
             }
' file1 file2 > file3
3

Thanks so much that works great. I'm sorry about not posting my code. I'm new. I'll post the code next time.

Cheers!:b:

4

No need to use awk. Can be all done within your shell if using a modern shell such as ksh93, bash or zsh.

#!/usr/bin/ksh93

while read pos; do
   print ${1:$pos-1:5}
done < file1
5

No need to use awk. Can be all done within your shell if using a modern shell such as ksh93, bash or zsh.

#!/usr/bin/ksh93

read file2

while read pos; do
   print ${file2:$pos-1:5}
done < file1

cat file2 | ./shellscript

or with no use of cat

./shellscript < file2