UNIX : Awk example to strip character of word

The below program will read all the first character of a line and join it together.

#!/bin/bash

F="file.txt"

for i in $(cat $F)
do
          echo $i | awk -F"_" 'BEGIN{ st="" } 
          { for( i=1; i<=NF; i++ )
          { st=st""toupper(substr($i,1,1)) }
          }
           END{ print st }'
done

The program will read a file with "_"(underscore) delimited content. Then all the first character of the line will be striped and joined together.

Eg:

File name : Word_File_Created_by_John"

Output : WFCBJ

Note then small case is also turned to upper case.

The below awk functions are used in this program

toupper() - This will convert the string to upper case
substr() - This will strip the specific character(s) from the string