CODEWITHSUNDEEP
linuxperlbashawk
user1121951
user1121951

Reputation:

Linux command or Bash syntax that calculate the next ASCII character

I have a Linux machine (Red Hat Linux 5.1), and I need to add the following task to my Bash script.

Which Linux command or Bash syntax will calculate the next ASCII character?

Remark – the command syntax can be also AWK/Perl, but this syntax must be in my Bash script.

Example:

 input                  results

 a    --> the next is   b
 c    --> the next is   d
 A    --> the next is   B

Upvotes: 7

Views: 1281

Answers (5)

user37421
user37421

Reputation: 435

The character value:

c="a"

To convert the character to its ASCII value:

v=$(printf %d "'$c")

The value you want to add to this ASCII value:

add=1

To change its ASCII value by adding $add to it:

((v+=add))

To convert the result to char:

perl -X -e "printf('The character is %c\n', $v);"

I used -X to disable all warnings

You can combine all of these in one line and put the result in the vairable $r:

c="a"; add=1; r=$(perl -X -e "printf('%c', $(($add+$(printf %d "'$c"))));")

you can print the result:

echo "$r"

You can make a function to return the result:

achar ()
{
     c="$1"; add=$2
     printf "$(perl -X -e "printf('%c', $(($add+$(printf %d "'$c"))));")"
}

you can use the function:

x=$(achar "a" 1) // x = the character that follows a by 1

or you can make a loop:

array=( a k m o )
for l in "${array[@]}"
do
     echo "$l" is followed by $(achar "$l" 1)
done

Upvotes: 0

BluesRockAddict
BluesRockAddict

Reputation: 15683

You could use chr() and ord() functions for Bash (see How do I convert an ASCII character to its decimal (or hexadecimal) value and back?):

# POSIX
# chr() - converts decimal value to its ASCII character representation
# ord() - converts ASCII character to its decimal value

Upvotes: 3

Tim
Tim

Reputation: 35933

Use translate (tr):

echo "aA mM yY" | tr "a-yA-Y" "b-zB-Z"

It prints:

bB nN zZ

Upvotes: 8

TLP
TLP

Reputation: 67908

Perl's ++ operator also handles strings, to an extent:

perl -nle 'print ++$_'

The -l option with autochomp is necessary here, since a\n for example will otherwise return 1.

Upvotes: 4

Artyom V. Kireev
Artyom V. Kireev

Reputation: 628

perl -le "print chr(ord(<>) + 1)"

Interactive:

breqwas@buttonbox:~$ perl -le "print chr(ord(<>) + 1)"
M
N

Non-interactive:

breqwas@buttonbox:~$ echo a | perl -le "print chr(ord(<>) + 1)"
b

Upvotes: 0

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