Rewriting Python SHA1 Digest code to Bash

Question

On Debian machines I run the following Python code:

#!/usr/bin/env python3

text_in = "abcd".encode('utf8')

sha1 = hashlib.sha1()
sha1.update(text_in)
raw_digest = sha1.digest()
text_out = base64.b64encode(raw_digest)

print( "text_in: " + str(text_in) )
print( "text_out: " + str(text_out) )

Below is the result of Python code:

text_in: abcd
text_out: gf6L/odXbD7LIkJvjleEc4KRes8=

It's TRUE.

I'm trying to rewrite this Python code to Bash code:

#!/bin/sh

TEXT_IN="abcd"

DIGEST=$( echo -n "$TEXT_IN" | sha1sum | awk '{print $1}' )
TEXT_OUT=$( echo -n "$DIGEST" | base64 )

echo "TEXT_IN: $TEXT_IN"
echo "TEXT_OUT: $TEXT_OUT"

Below is the result of my Bash code:

TEXT_IN: abcd
TEXT_OUT: ODFmZThiZmU4NzU3NmMzZWNiMjI0MjZmOGU1Nzg0NzM4MjkxN2FjZg==

It's FALSE.

I need to run this Bash code in OpenWRT which is low on disk space and uses easy code in scripts, lightweight software and simple solutions.

Please help me rewrite this code from Python to Bash.

Answer 1

Try this Shellcheck-clean (except for a spurious warning about using a variable in the printf format string) Bash code:

#!/bin/bash -p

text_in='abcd'

printf_fmt=$(printf '%s' "$text_in" | sha1sum  \
                | sed -e 's/[[:space:]].*$//' -e 's/../\\x&/g')
text_out=$(printf "$printf_fmt" | base64)

printf 'text_in: %s\n' "$text_in"
printf 'text_out: %s\n' "$text_out"

• See Correct Bash and shell script variable capitalization for an explanation of why the code does not use ALL_UPPERCASE variable names.
• See the accepted, and excellent, answer to Why is printf better than echo? for an explanation of why the code uses printf everywhere instead of echo.
• Note that you have tagged the question with bash but presented sh code. They are different. See Difference between sh and Bash. The code above may not work with sh instead of bash because the printf in some sh implementations does not support \x in format strings.