sh遇到问题，求指点

cxdwlc

这是一个开发板自带的c6run-environment.sh，作用是增加一些变量，执行应该没有问题，但在虚拟机里执行./c6run-environment.sh 之后没有效果，echo不出增加的变量，求高手指出问题所在！！
#!/bin/bash
# /usr/local/dvsdk/c6run_0_98_03_03/c6run-environment.sh environment script
: ${CODEGEN_INSTALL_DIR='/usr/local/dvsdk/cgt6x_6_1_14'}
export CODEGEN_INSTALL_DIR
: ${C6RUN_TOOLCHAIN_PATH='/usr/local/dvsdk/c6run_0_98_03_03'}
export C6RUN_TOOLCHAIN_PATH
: ${DSP_CFLAGS='-mv6740'}
export DSP_CFLAGS
: ${ARM_TOOLCHAIN_PATH='/usr/local/dvsdk/linux-devkit/'}
export ARM_TOOLCHAIN_PATH
: ${ARM_TOOLCHAIN_PREFIX='arm-arago-linux-gnueabi-'}
export ARM_TOOLCHAIN_PREFIX
: ${CFLAGS='-mcpu=arm926ej-s -mlittle-endian -mfloat-abi=soft'}
export CFLAGS
: ${PLATFORM_CFLAGS='-DDSP_REGION_BASE_ADDR=0xC2000000 -DDSP_REGION_CMEM_SIZE=0x01000000 -DDSP_REGION_CODE_SIZE=0x01000000'}
export PLATFORM_CFLAGS

求指点