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Print the given git hash + a prepended "1" in decimal form
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#!/bin/bash -euo pipefail | |
if [ ${#} -eq 0 ] | |
then | |
# read from STDIN | |
MAYBE_GIT_HASH=$( cat ) | |
else | |
MAYBE_GIT_HASH="${1}" | |
fi | |
LEGAL_GIT_HASH_CHARACTERS="0123456789ABCDEFabcdef" | |
# grep regex doesn't allow + metacharacter :( | |
HASH_GREP_REGEX='^['"${LEGAL_GIT_HASH_CHARACTERS}"']['"${LEGAL_GIT_HASH_CHARACTERS}"']*$' | |
GIT_HASH=$( echo "${MAYBE_GIT_HASH}" | grep "${HASH_GREP_REGEX}" ) || { | |
echo "\"${MAYBE_GIT_HASH}\" doesnt look like a git hash. A git hash should have only: \"${LEGAL_GIT_HASH_CHARACTERS}\"" >&2 | |
exit 1 | |
} | |
# We must prefix the git hash with a 1 | |
# If it starts with a zero, when we decimalize it, | |
# and later hexify it, we'll lose the zero. | |
ONE_PREFIXED_GIT_HASH=1"${GIT_HASH}" | |
# bc requires hex to be uppercase because | |
# lowercase letters are reserved for bc variables | |
UPPERCASE_ONE_PREFIXED_GIT_HASH=$( echo "${ONE_PREFIXED_GIT_HASH}" | tr "[:lower:]" "[:upper:]" ) | |
# convert to decimal | |
# See "with bc": http://stackoverflow.com/a/13280173/9636 | |
echo "ibase=16;obase=A;${UPPERCASE_ONE_PREFIXED_GIT_HASH}" | bc |
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