Generating the Alphabet

[chipperMDW]

Occasionally, I'll need to write a script that does something for each letter in the alphabet. I used do something like:

for x in 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; do
    echo $x
done

That's tedious to type, and it always seemed like there should be a better way, like a [tt]seq[/tt] for letters. I recently discovered a tool called [tt]jot[/tt]. With it, I can do the following:

for x in $([highlight]jot -c 26 a[/highlight]); do  # Generate 26 characters starting at ASCII 'a'
    echo $x
done

I was curious about what other methods people had for accomplishing the same task. I'm sure there are some nifty perl and awk one-liners.

I'm especially curious to see if there's a way to do this that doesn't involve a dependence on ASCII codes and works with POSIX [tt][:alpha:][/tt]-style character classes.

 

[PHV]

for x in $(awk 'BEGIN{for(i=97;i<=122;++i)printf "%c\n",i}'); do # Generate 26 characters starting at ASCII 'a'
echo $x
done

Hope This Helps, PH.
Want to get great answers to your Tek-Tips questions? Have a look at FAQ219-2884 or FAQ181-2886

 

[mrn]

Put all yours functions in one file 'functions.ksh'

--- function.sh ---
alphabet () {
for x in 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; do
echo $x
done
}



In your main script, source the functions file :


--- Main script ---
# source functions definitions
. functions.sh
# now all functions are available



Mike

"A foolproof method for sculpting an elephant: first, get a huge block of marble, then you chip away everything that doesn't look like an elephant."

http://www.airport-parking-site.co.uk/

 

[olded]

You can also build a function once and use it many times:

!#/bin/ksh

function print_alpha {
echo "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"
}

for x in $(print_alpha); do
   echo $x
done

 

[stefanwagner]

for dec in $(seq 65 90)
do 
    oct=$(printf "\%o " $dec)
    echo -e $oct
done

Don't know how portable it is, and how to condense it further.

According to man seq, seq -f "%03o" 65 77 should produce octal numbers itself. It doesn't! Crap!

printf "%c\n" 65 doesn't print an A, but 6. Crap too!

Or am I wrong?

seeking a job as java-programmer in Berlin:

http://home.arcor.de/hirnstrom/bewerbung

 

[futurelet]

ruby -e '("A".."Z").each{|c| puts c}'

 

[futurelet]

printf "%c\n" 65 doesn't print an A, but 6.

Your forgot the comma.

printf "%c\n", 65

 

[chipperMDW]

According to man seq, seq -f "%03o" 65 77 should produce octal numbers itself. It doesn't! Crap!

printf "%c\n" 65 doesn't print an A, but 6. Crap too!

Or am I wrong?

I'm not sure. I saw the [tt]-f[/tt] flag to [tt]seq[/tt], but my manual says:

[b]-f, --format[/b]=[u]FORMAT[/u]
      use printf style floating-point FORMAT (default: %g)

and my info manual says

`-f FORMAT'
`--format=FORMAT'
     Print all numbers using FORMAT; default `%g'.  FORMAT must contain
     exactly one of the floating point output formats `%e', `%f', or
     `%g'.

Not sure why it should be limited to those format values, though. Maybe that's a bug.

 

[stefanwagner]

Hm.
My german manpage does not mention floating points at all.
Poor translation!
Calling the english manpage as root gives the hint.

printf "%c\n", 65

just prints an additional comma:
6
,

seeking a job as java-programmer in Berlin:

http://home.arcor.de/hirnstrom/bewerbung

 

[p5wizard]

printf man page (AIX53) states:

c
Accepts a value as a string and prints the first character
in the string.

You get a '6' because '6' is the first char of the string "65"


HTH,

p5wizard