Hex to decimal conversion in bash without using gawk - bash

Question

Input:
cat test1.out
12 , maze|style=0x48570006, column area #=0x7, location=0x80000d
13 , maze|style=0x48570005, column area #=0x7, location=0x80aa0d
....
...
..
.
Output needed:
12 , maze|style=0x48570006, column area #=0x7, location=8388621 <<<8388621 is decimal of 0x80000d
....
I want to convert just the last column to decimal.
I cannot use gawk as it is not available in our company machines everywhere.
Tried using awk --non-decimal-data but it didnt work also.
Wondering if just printf command can work on flipping the last word from hex to decimal.
Any other ideas that you can suggest?

Answer 1

There's no need for awk or any other external commands here: bash's native math operation handle hexadecimal values correctly when in an arithmetic context (this is why echo $((0xff)) emits 255).
#!/usr/bin/env bash
# ^^^^- must be really bash, not /bin/sh
location_re='location=(0x[[:xdigit:]]+)([[:space:]]|$)'
while read -r line; do
if [[ $line =~ $location_re ]]; then
hex=${BASH_REMATCH[1]}
dec=$(( $hex ))
printf '%s\n' "${line/location=$hex/location=$dec}"
else
printf '%s\n' "$line"
fi
done
You can see this running at https://ideone.com/uN7qNY

Answer 2

Considering the case strtonum() function is not available, how about:
#!/bin/bash
awk -F'location=0x' '
function hex2dec(str,
i, x, c, tab) {
for (i = 0; i <= 15; i++) {
tab[substr("0123456789ABCDEF", i + 1, 1)] = i;
}
x = 0
for (i = 1; i <= length(str); i++) {
c = toupper(substr(str, i, 1))
x = x * 16 + tab[c]
}
return x
}
{
print $1 "location=" hex2dec($2)
}
' test1.out
where hex2dec() is a homemade substituion of strtonum().

Answer 3

Wait, can't you just use printf in other awks? It won't work with gawk but it does with other awks, right? For example with mawk:
$ mawk 'BEGIN{FS=OFS="="}{$NF=sprintf("%d", $NF);print}' file
12 , maze|style=0x48570006, column area #=0x7, location=8388621
13 , maze|style=0x48570005, column area #=0x7, location=8432141
I tested with mawk, awk-20070501, awk-20121220 and Busybox awk.
Discarded after edit but left for comments' sake:
Using rev and cut to extract around the last = and printf for hex2dec conversion:
$ while IFS='' read -r line || [[ -n "$line" ]]
do
printf "%s=%d\n" "$(echo "$line" | rev | cut -d = -f 2- | rev)" \
$(echo "$line" | rev | cut -d = -f 1 | rev)
done < file
Output:
12 , maze|style=0x48570006, column area #=0x7, location=8388621
13 , maze|style=0x48570005, column area #=0x7, location=8432141

Answer 4

If you have Perl installed, not having Gawk is rather inconsequential.
perl -pe 's/location=\K0x([0-9a-f]+)/ hex($1) /e' file

Answer 5

This might work for you (GNU sed and Bash):
sed 's/\(.*location=\)\(0x[0-9a-f]\+\)/echo "\1$((\2))"/Ie' file
Use pattern matching and back references to split each line and then evaluate an echo command.
Alternative:
sed 's/\(.*location=\)\(0x[0-9a-f]\+\)/echo "\1$((\2))"/I' file | sh

Answer 6

BASH_REMATCH array info :
http://molk.ch/tips/gnu/bash/rematch.html
quintessential principe :
[[ string =~ regexp ]]
[[ "abcdef" =~ (b)(.)(d)e ]]
If the 'string' matches 'regexp',
.. the matched part of the string is stored in the BASH_REMATCH array.
# Now:
# BASH_REMATCH[0]=bcde # as the total match
# BASH_REMATCH[1]=b # as the 1'th captured group
# BASH_REMATCH[2]=c # as ...
# BASH_REMATCH[3]=d
enjoy !

Answer 7

Bash's native math operation handles hexadecimal values correctly anytime.
Example:
echo $(( 0xff))
255
printf '%d' 0xf0
240