shell脚本输出没换行符

问题如下：在终端里输入dmesg | grep -i speed命令显示如下

[    1.358314] xhci_hcd 0000:00:14.0: Host supports USB 3.0 SuperSpeed
[    1.690882] usb 1-3: new full-speed USB device number 2 using xhci_hcd
[    1.966868] usb 2-1: new SuperSpeed Gen 1 USB device number 2 using xhci_hcd
[    2.114826] usb 1-6: new high-speed USB device number 3 using xhci_hcd
[    2.426891] usb 1-8: new full-speed USB device number 4 using xhci_hcd
[    2.702893] usb 1-11: new full-speed USB device number 5 using xhci_hcd

在脚本中输出的没有换行符，如下

$ USB_T1=$(dmesg | grep -i speed)
$ echo $USB_T1
[ 1.358314] xhci_hcd 0000:00:14.0: Host supports USB 3.0 SuperSpeed [ 1.690882] usb 1-3: new full-speed USB device number 2 using xhci_hcd [ 1.966868] usb 2-1: new SuperSpeed Gen 1 USB device number 2 using xhci_hcd [ 2.114826] usb 1-6: new high-speed USB device number 3 using xhci_hcd [ 2.426891] usb 1-8: new full-speed USB device number 4 using xhci_hcd [ 2.702893] usb 1-11: new full-speed USB device number 5 using xhci_hcd

解决方法：
使用$ echo "$USB_T1",echo时加上双引号就可以解决问题。