shell的printf输出时包含空格问题

代码：

printf "%-30s:%-15s\n" report_selinux_enable $report_selinux_enable
printf "%-30s:%-15s\n" report_selinux_status $report_selinux_status
printf "%-30s:%-15s\n" report_os $report_os
printf "%-30s:%-15s\n" report_hostname $report_hostname
printf "%-30s:%-15s\n" report_kernel $report_kernel
printf "%-30s:%-15s\n" report_uptime $report_uptime
printf "%-30s:%-15s\n" report_date_time $report_date_time

输出：

report_selinux_enable         :disabled       
report_selinux_status         :Disabled       
report_os                     :GNU/Linux      
report_hostname               :centos.com     
report_kernel                 :3.10.0-693.2.2.el7.x86_64
report_uptime                 :42             
days                          :               
report_date_time              :2018-07-18-20-24-23

可以看出输出的在线天数（report_uptime）的值是42（本来是42 days），下面还有一行显示的有问题，把一行拆成了两行显示，是因为report_uptime的值中间有空格，所以被拆成两行

解决：printf语句后面的引用值要放在""中

printf "%-30s:%-15s\n" report_uptime "$report_uptime"

printf "%-30s:%-15s\n" "report_selinux_enable" "$report_selinux_enable"
printf "%-30s:%-15s\n" "report_selinux_status" "$report_selinux_status"
printf "%-30s:%-15s\n" "report_os" "$report_os"
printf "%-30s:%-15s\n" "report_hostname" "$report_hostname"
printf "%-30s:%-15s\n" "report_kernel" "$report_kernel"
printf "%-30s:%-15s\n" "report_uptime" "$report_uptime"
printf "%-30s:%-15s\n" "report_uptime" "$report_date_time"

report_selinux_enable         :disabled       
report_selinux_status         :Disabled       
report_os                     :GNU/Linux      
report_hostname               :centos.com     
report_kernel                 :3.10.0-693.2.2.el7.x86_64
report_uptime                 :42 days        
report_date_time              :2018-07-18-20-27-40