Bash Shell使用技巧

1. Makefile与Shell取环境变量的不同方法

Makefile: cc=$(CROSS_COMPILE)

Shell: cc=$CROSS_COMPILE

 

2.从命令中得到值

removable=$(cat /sys/block/$1/removable)

 

3. while

export TSLIB_TSDEVICE=/dev/ts
counter=1
while [ 1 ] --> 无限循环

while [ $counter -lt 10 ]
do
        aplay music.wav &
        ts_test &
        counter_inner=1
        while [ $counter_inner -lt 60 ]
        do
                sleep 4
                counter_inner=$(( $counter_inner + 1 ))
        done
        pkill ts_test
        counter=$(( $counter + 1 ))
        echo "the counter is $counter"
done

 

4. For

for file in $( find . -type f -name "*.bz2" | sort )
do
        tar xvfj $file -C /scratch/paul/lite/linux/src/
done

 

5. 如何过滤bash的错误输出?

arm-none-linux-gnueabi-gcc -v 2>/dev/null

 

stdin 0<

stdout 1>

stderr 2>