Main ：
exec - 永久重定向命令，exec命令启动一个新的shell并将所有STDOUT文件描述符重定向到文件，脚本中输出的所有文件会被STDOUT到文件
#!/bin/bash
#
#################################################
# parameters for script
# du -S /var/log | sort -rn | sed ‘{11,$D;=}‘ | sed ‘N; s/\n/ /‘ | gawk ‘{printf ":" $1 "\t" $2 "\t" $3 "\n"}‘
#
################# Main script ################################
#
dir_check="/var/log/ /home/* "
#
DATE=$(date "+%y%m%d")
#
exec 1>> disk_space_$DATE.rpt #Make report file stdout
#
echo
echo "#1.Top ten disk space usage"
echo "#2.the $dir_check directory"
echo
#
for check_loop in $dir_check
do
du -S $check_loop | sort -rn | sed ‘{11,$D;=}‘ | sed ‘N; s/\n/ /‘ | gawk ‘{printf $1 ")" "\t" $2 "\t" $3 "\n"}‘
done
#
#
原文：https://www.cnblogs.com/liii/p/12203603.html