Appendix T. ASCII Table

Traditionally, a book of this sort has an ASCII Table appendix. This book does not. Instead, here are several short scripts, each of which generates a complete ASCII table.


Example T-1. A script that generates an ASCII table

   1 #!/bin/bash
   2 # ascii.sh
   3 # ver. 0.2, reldate 26 Aug 2008
   4 # Patched by ABS Guide author.
   5 
   6 # Original script by Sebastian Arming.
   7 # Used with permission (thanks!).
   8 
   9 exec >ASCII.txt         #  Save stdout to file,
  10                         #+ as in the example scripts
  11                         #+ reassign-stdout.sh and upperconv.sh.
  12 
  13 MAXNUM=256
  14 COLUMNS=5
  15 OCT=8
  16 OCTSQU=64
  17 LITTLESPACE=-3
  18 BIGSPACE=-5
  19 
  20 i=1 # Decimal counter
  21 o=1 # Octal counter
  22 
  23 while [ "$i" -lt "$MAXNUM" ]; do  # We don't have to count past 400 octal.
  24         paddi="    $i"
  25         echo -n "${paddi: $BIGSPACE}  "       # Column spacing.
  26         paddo="00$o"
  27 #       echo -ne "\\${paddo: $LITTLESPACE}"   # Original.
  28         echo -ne "\\0${paddo: $LITTLESPACE}"  # Fixup.
  29 #                   ^
  30         echo -n "     "
  31         if (( i % $COLUMNS == 0)); then       # New line.
  32            echo
  33         fi
  34         ((i++, o++))
  35         # The octal notation for 8 is 10, and 64 decimal is 100 octal.
  36         (( i % $OCT == 0))    && ((o+=2))
  37         (( i % $OCTSQU == 0)) && ((o+=20))
  38 done
  39 
  40 exit $?
  41 
  42 # Compare this script with the "pr-asc.sh" example.
  43 # This one handles "unprintable" characters.
  44 
  45 # Exercise:
  46 # Rewrite this script to use decimal numbers, rather than octal.


Example T-2. Another ASCII table script

   1 #!/bin/bash
   2 # Script author: Joseph Steinhauser
   3 # Lightly edited by ABS Guide author, but not commented.
   4 # Used in ABS Guide with permission.
   5 
   6 #-------------------------------------------------------------------------
   7 #-- File:  ascii.sh    Print ASCII chart, base 10/8/16         (JETS-2012)
   8 #-------------------------------------------------------------------------
   9 #-- Usage: ascii [oct|dec|hex|help|8|10|16]
  10 #--
  11 #-- This script prints out a summary of ASCII char codes from Zero to 127.
  12 #-- Numeric values may be printed in Base10, Octal, or Hex.
  13 #--
  14 #-- Format Based on: /usr/share/lib/pub/ascii with base-10 as default.
  15 #-- For more detail, man ascii . . .
  16 #-------------------------------------------------------------------------
  17 
  18 [ -n "$BASH_VERSION" ] && shopt -s extglob
  19 
  20 case "$1" in
  21    oct|[Oo]?([Cc][Tt])|8)       Obase=Octal;  Numy=3o;;
  22    hex|[Hh]?([Ee][Xx])|16|[Xx]) Obase=Hex;    Numy=2X;;
  23    help|?(-)[h?])        sed -n '2,/^[ ]*$/p' $0;exit;;
  24    code|[Cc][Oo][Dd][Ee])sed -n '/case/,$p'   $0;exit;;
  25    *) Obase=Decimal
  26 esac # CODE is actually shorter than the chart!
  27 
  28 printf "\t\t## $Obase ASCII Chart ##\n\n"; FM1="|%0${Numy:-3d}"; LD=-1
  29 
  30 AB="nul soh stx etx eot enq ack bel bs tab nl vt np cr so si dle"
  31 AD="dc1 dc2 dc3 dc4 nak syn etb can em sub esc fs gs rs us sp"
  32 
  33 for TOK in $AB $AD; do ABR[$((LD+=1))]=$TOK; done;
  34 ABR[127]=del
  35 
  36 IDX=0
  37 while [ $IDX -le 127 ] && CHR="${ABR[$IDX]}"
  38    do ((${#CHR}))&& FM2='%-3s'|| FM2=`printf '\\\\%o  ' $IDX`
  39       printf "$FM1 $FM2" "$IDX" $CHR; (( (IDX+=1)%8))||echo '|'
  40    done
  41 
  42 exit $?


Example T-3. A third ASCII table script, using awk

   1 #!/bin/bash
   2 # ASCII table script, using awk.
   3 # Author: Joseph Steinhauser
   4 # Used in ABS Guide with permission.
   5 
   6 
   7 #-------------------------------------------------------------------------
   8 #-- File:  ascii     Print ASCII chart, base 10/8/16         (JETS-2010)
   9 #-------------------------------------------------------------------------
  10 #-- Usage: ascii [oct|dec|hex|help|8|10|16]
  11 #--
  12 #-- This script prints a summary of ASCII char codes from Zero to 127.
  13 #-- Numeric values may be printed in Base10, Octal, or Hex (Base16).
  14 #--
  15 #-- Format Based on: /usr/share/lib/pub/ascii with base-10 as default.
  16 #-- For more detail, man ascii
  17 #-------------------------------------------------------------------------
  18 
  19 [ -n "$BASH_VERSION" ] && shopt -s extglob
  20 
  21 case "$1" in
  22    oct|[Oo]?([Cc][Tt])|8)       Obase=Octal;  Numy=3o;;
  23    hex|[Hh]?([Ee][Xx])|16|[Xx]) Obase=Hex;    Numy=2X;;
  24    help|?(-)[h?])        sed -n '2,/^[ ]*$/p' $0;exit;;
  25    code|[Cc][Oo][Dd][Ee])sed -n '/case/,$p'   $0;exit;;
  26    *) Obase=Decimal
  27 esac
  28 export Obase   # CODE is actually shorter than the chart!
  29 
  30 awk 'BEGIN{print "\n\t\t## "ENVIRON["Obase"]" ASCII Chart ##\n"
  31            ab="soh,stx,etx,eot,enq,ack,bel,bs,tab,nl,vt,np,cr,so,si,dle,"
  32            ad="dc1,dc2,dc3,dc4,nak,syn,etb,can,em,sub,esc,fs,gs,rs,us,sp"
  33            split(ab ad,abr,",");abr[0]="nul";abr[127]="del";
  34            fm1="|%0'"${Numy:- 4d}"' %-3s"
  35            for(idx=0;idx<128;idx++){fmt=fm1 (++colz%8?"":"|\n")
  36            printf(fmt,idx,(idx in abr)?abr[idx]:sprintf("%c",idx))} }'
  37 
  38 exit $?