Shell Programming and Scripting

asciinext()
{
  printf "\\$(printf "%03o" $(( $(printf "%d" \'$1 ) + 1 )) )\n" 
}

$ asciinext a
b

 $ echo "a" | ruby -e 'puts gets.succ' 
b

#!/bin/ksh
A=( A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
    a b c d e f g h i j k l m n o p q r s t u v w x y z )
INC=$1
CNT=${#A[@]}
SU=$(printf "%d" \'A)
EU=$(printf "%d" \'Z)
SL=$(printf "%d" \'a)
EL=$(printf "%d" \'z)
shift
echo $@ | while read -n 1 L
do
   i=0
   p=$(printf "%d" \'$L)
   n=99
   [ $p -ge $SU -a $p -le $EU ] && n=$(( (p-SU+INC)%CNT))
   [ $p -ge $SL -a $p -le $EL ] && n=$(( (26+p-SL+INC)%CNT))
   [ $n -eq 99 ] && printf "$L" || printf "%s" ${A[n]}
done
echo

$ ./shift.ksh 1 Zhis is z test
aijt jt A uftu
 
$ ./shift.ksh 26 Zhis is z test
zHIS IS Z TEST
 
$ ./shift.ksh -2 $(./shift.ksh 2 This is a test)
This is a test