In the GUI, click the Shell menu on the left. Once it comes up, type that command into the prompt.
da0p2 DEGRADED 0 0 166 too many errors
da1p2 ONLINE 0 0 162
errors: Permanent errors have been detected in the following files:
//usr/local/sbin/pkg-static
//usr/local/sbin/resize2fs
//usr/local/sbin/smartctl
//usr/local/sbin/storcli
//usr/local/sbin/tcsd_emu
//usr/local/www/dojo/dojo/cldr/nls/ar/buddhist.js
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/sbin/dnssec-revoke
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/go/src/runtime/asm_amd64.s
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/go/src/runtime/defs_linux_ppc64.go
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/sbin/dnssec-settime
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/lib/samba/libsmbd-base-samba4.so
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/sbin/dnssec-signzone
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/lib/shared-modules/pdb/ldapsam.so
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/www/dojo/dojo/cldr/nls/fi/generic.js
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/sbin/grub-install
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/libexec/git-core/git-http-backend
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/go/pkg/tool/freebsd_amd64/doc
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/libexec/git-core/git-http-push
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/go/pkg/tool/freebsd_amd64/link
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/go/pkg/tool/freebsd_amd64/nm
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/go/pkg/tool/freebsd_amd64/pack
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/go/pkg/tool/freebsd_amd64/pprof
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/share/fonts/dejavu/DejaVuSans-Bold.ttf
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/share/fonts/dejavu/DejaVuSans-BoldOblique.ttf
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/share/fonts/dejavu/DejaVuSans-Oblique.ttf
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/share/fonts/dejavu/DejaVuSansCondensed-Bold.ttf
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/lib/sasl2/libscram.so.3.0.0
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/sbin/iprop-log
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/libexec/git-core/git-remote-https
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/share/man/man1/expand.1.gz
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/go/src/runtime/race/race_darwin_amd64.syso
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/sbin/pkg-static
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/share/info/heimdal.info.gz
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/go/src/runtime/race/race_windows_amd64.syso
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/lib/samba/libgensec-samba4.so
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/lib/shared-modules/ldb/dirsync.so
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/go/src/cmd/vendor/golang.org/x/arch/arm/armasm/tables.go
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/sbin/smartctl
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/go/src/regexp/syntax/simplify_test.go
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/www/dojo/dijit/form/_ComboBoxMenu.js.uncompressed.js
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/lib/samba/libsamba-net-samba4.so
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/lib/samba/libsamdb-common-samba4.so
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/sbin/dnssec-dsfromkey
freenas-boot/ROOT/11.1-U7@2018-05-06-21:06:05:/usr/local/go/src/runtime/type.go
[root@freenas ~]#