bash/snippets/read_first_char_of_file.sh
2018-04-30 02:53:44 +02:00

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#!/usr/bin/env bash
# - Read first charactor of a file:
# -
# - head -c1 <path-to-file>
deb_major_version=""
is_number() {
return $(test ! -z "${1##*[!0-9]*}" > /dev/null 2>&1);
# - also possible
# -
#[[ ! -z "${1##*[!0-9]*}" ]] && return 0 || return 1
#return $([[ ! -z "${1##*[!0-9]*}" ]])
}
if [[ -f "/etc/debian_version" ]]; then
deb_major_version=$(head -c1 /etc/debian_version)
if is_number $deb_major_version ; then
echo -e "\n\tDebian Major Version: $deb_major_version\n"
else
echo -e "\n\tNo numeric Version given. Debian Version: $(head -1 /etc/debian_version)\n"
fi
else
echo -e "\nFile '/etc/debian_version' not found"
fi
exit 0