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#!/bin/sh -e
# Modified from Debian's add-shell to work on OS X
if test $# -eq 0
then
echo "usage: $0 shellname [shellname ...]"
exit 1
fi
scriptname=$(basename "$0")
if [ "$(id -u)" -ne 0 ]; then
echo "${scriptname} must be run as root"
exit 1
fi
file=/etc/shells
# I want this to be GUARANTEED to be on the same filesystem as $file
tmpfile=${file}.tmp
set -o noclobber
# shellcheck disable=SC2064
trap "rm -f $tmpfile" EXIT
if ! cat $file > $tmpfile
then
cat 1>&2 <<EOF
Either another instance of $0 is running, or it was previously interrupted.
Please examine ${tmpfile} to see if it should be moved onto ${file}.
EOF
exit 1
fi
# Append a newline if it doesn't exist
[ -z "$(tail -c1 "$tmpfile")" ] || echo "" >> "$tmpfile"
for i
do
if ! grep -q "^${i}$" "$tmpfile"
then
echo "$i" >> "$tmpfile"
fi
done
chmod 0644 $tmpfile
chown root:wheel $tmpfile
mv $tmpfile $file
trap "" EXIT
exit 0
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