GCC_OLD=296
GCC_NEW=323

cd /usr/bin
if [ ! -r gcc$GCC_NEW ]; then mv gcc gcc$GCC_NEW; fi
if [ ! -r g++$GCC_NEW ]; then mv g++ g++$GCC_NEW; fi

if [ "$1" = "" ]; then
echo Please input gcc version, ...{value} = $GCC_OLD OR $GCC_NEW
echo ---OOO---OOO---OOO---OOO---OOO---OOO---OOO---!
else
if [ "$1" = "$GCC_OLD" -o "$1" = "$GCC_NEW" ]; then
rm -f gcc g++
ln -s gcc$1 gcc
ln -s g++$1 g++
else
echo Wrong input gcc version, ...{value} = $GCC_OLD OR $GCC_NEW
echo ---XXX---XXX---XXX---XXX---XXX---XXX---XXX---!!
fi
fi
ls -la gcc* g++*

chmod +x /usr/bin/mc

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vi /usr/bin/mn