if [ -z ${VAR+x} ]
then
echo "VAR not exist"
else
echo "$VAR"
fi
- date +%N |cut -c 1-8 #随机8个数字
- echo $RANDOM |md5sum |cut -c 1-8 #随机8个字符
ps aux --sort=-%cpu | awk 'NR==1{print $2,$3,$11}NR>1{if($3!=0.0) print $2,$3,$11}' > some_file.txt
grep -c 'model name' /proc/cpuinfo