常写dockerfile的话会经常用到EOF命令，现在记录两条常用的
以下两种方式结果一致：
cat > envb.sh << EOF
export PATH=/x64-gcc9/bin:
export LD_LIBRARY_PATH=/x64-gcc9/lib:/x64-gcc9/lib64:
EOF
cat << EOF > test.sh
export PATH=/x64-gcc9/bin:
export LD_LIBRARY_PATH=/x64-gcc9/lib:/x64-gcc9/lib64:
EOF
