BASH binary to Hex to match PHP bin2hex function?

Question

In bash I can call PHP and run the following:

testKey='8798(*&98}9%"^8&]8_98{9798**76876'
testHex=$(php -r "echo bin2hex('$testKey');")
echo $testHex

And that will result in 38373938282a2639387d3925225e38265d385f39387b393739382a2a3736383736

I've got a system where PHP isn't available, is there anyway to get the same result using just bash ?

Thanks

score 4 · Accepted Answer · answered May 07 '20 at 08:28

If you have hexdump lying around:

$ printf "%s" "$testKey" | hexdump -ve '/1 "%x"'
38373938282a2639387d3925225e38265d385f39387b393739382a2a3736383736

-e sets a format string for hexdump, which 'must be surrounded by double quote ( " ) marks'. /1 uses one byte at a time for the format string %x, which prints it in hex (otherwise the byte order could result in different output). -v is to make it print repeated data as well (the default is to replace them with a *).

Thanks this works perfectly. – user214292 May 07 '20 at 11:17 — user214292, May 07 '20 at 11:17

noAnton · Answer 2 · 2020-05-07T08:36:16.860

2

Yes, with xxd you can do exactly the same:

testKey='8798(*&98}9%"^8&]8_98{9798**76876'
testHex=$(echo -n "${testKey}" | xxd -p -c 100)

The -p flag is for a hex dump without offset information.
The -c 100 flag is for a line-length of 100 characters(default is 16, max 256).

edited May 07 '20 at 08:36

answered May 07 '20 at 08:27

noAnton

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Why does your output contain the `0a` in the end? – GMaster May 07 '20 at 08:31
ah, thats the newline added by <<< i will fix this – noAnton May 07 '20 at 08:34

score 0 · Answer 3 · answered May 07 '20 at 12:52

With "just bash", using a trick from BASH print question (printf \$(printf '%03o' $1))

$ for ((i=0;i<${#testKey};i++)); do printf '%x' "$(printf "'%c" "${testKey:i:1}")"; done; echo
38373938282a2639387d3925225e38265d385f39387b393739382a2a3736383736

With perl's unpack

$ perl -E 'say unpack "H*", $ARGV[0]' "$testKey"
38373938282a2639387d3925225e38265d385f39387b393739382a2a3736383736

BASH binary to Hex to match PHP bin2hex function?

3 Answers3