Shell Programming and Scripting

$ echo "78" | awk '{ printf "%c\n", $0 }'
N
$ awk 'BEGIN{ printf "%c\n", "78" }' /dev/null
N

$ echo "78" | awk '{ printf "%c\n", $0 }'
N
$ awk 'BEGIN{ printf "%c\n", "78" }' /dev/null
7

awk 'BEGIN{ printf "%c\n", "78" }'

awk 'BEGIN{ printf "%c\n", 78 }'

echo "78" | awk '{ printf "%c\n", $0 }'

echo "78" | awk '{ printf "%c\n", $0"" }'

$ try() { for awk in gawk mawk oawk bawk; do printf '%s: ' "$awk"; $awk "$@"; done; }
$ try 'BEGIN{ printf "%c\n", "78" }' /dev/null
gawk: 7
mawk: 7
oawk: N
bawk: 7

for awk in gawk mawk oawk bawk; do printf '%s: ' "$awk"; echo 78 | $awk '{ printf "%c\n", $0 "" }'; done;
gawk: 7
mawk: 7
oawk: N
bawk: 7

$ cat file
796f6461

awk '
        {
                for ( i = 1; i <= length($0); i += 2 )
                {
                        hex = sprintf ( "0x%s", substr ( $0, i, 2 ) )
                        dec = sprintf ( "%d", strtonum ( hex ) )
                        sym = sprintf ( "%c", dec )
                        s = s ? s sym : sym
                }
        }
        END {
                print s
        }
' file
1119

awk '
        {
                for ( i = 1; i <= length($0); i += 2 )
                {
                        hex = sprintf ( "0x%s", substr ( $0, i, 2 ) )
                        dec = sprintf ( "%d", strtonum ( hex ) )
                        dec = dec + 0
                        sym = sprintf ( "%c", dec )
                        s = s ? s sym : sym
                }
        }
        END {
                print s
        }
' file
yoda