LDP/LDP/guide/docbook/abs-guide/ascii.sh

#!/bin/bash
# ascii.sh
# ver. 0.2, reldate 26 Aug 2008
# Patched by ABS Guide author.

# Original script by Sebastian Arming.
# Used with permission (thanks!).

exec >ASCII.txt         #  Save stdout to file,
                        #+ as in the example scripts
                        #+ reassign-stdout.sh and upperconv.sh.

MAXNUM=256
COLUMNS=5
OCT=8
OCTSQU=64
LITTLESPACE=-3
BIGSPACE=-5

i=1 # Decimal counter
o=1 # Octal counter

while [ "$i" -lt "$MAXNUM" ]; do  # We don't have to count past 400 octal.
        paddi="    $i"
        echo -n "${paddi: $BIGSPACE}  "       # Column spacing.
        paddo="00$o"
#       echo -ne "\\${paddo: $LITTLESPACE}"   # Original.
        echo -ne "\\0${paddo: $LITTLESPACE}"  # Fixup.
#                   ^
        echo -n "     "
        if (( i % $COLUMNS == 0)); then       # New line.
           echo
        fi
        ((i++, o++))
        # The octal notation for 8 is 10, and 64 decimal is 100 octal.
        (( i % $OCT == 0))    && ((o+=2))
        (( i % $OCTSQU == 0)) && ((o+=20))
done

exit $?

# Compare this script with the "pr-asc.sh" example.
# This one handles "unprintable" characters.

# Exercise:
# Rewrite this script to use decimal numbers, rather than octal.