Binary file (standard input) matches

Error code:

$ sudo cat /var/log/syslog | grep "tree"
Binary file (standard input) matches

Solution:

$ sudo cat /var/log/syslog | grep "tree" --text
Jul 14 17:43:00 osboxes kernel: [    3.042582] vboxguest: loading out-of-tree module taints kernel.
Jul 15 13:24:47 osboxes kernel: [    3.420002] vboxguest: loading out-of-tree module taints kernel.
Jul 15 13:54:22 osboxes kernel: [    3.027623] vboxguest: loading out-of-tree module taints kernel.
Sep 28 12:59:21 osboxes kernel: [    3.165531] vboxguest: loading out-of-tree module taints kernel.
Sep 28 13:46:04 osboxes kernel: [    2.755048] vboxguest: loading out-of-tree module taints kernel.
Sep 28 13:51:08 osboxes kernel: [    3.508174] vboxguest: loading out-of-tree module taints kernel.
Oct 19 21:04:41 osboxes kernel: [    2.762903] vboxguest: loading out-of-tree module taints kernel.
Oct 19 21:11:51 osboxes kernel: [    2.566860] vboxguest: loading out-of-tree module taints kernel.