Search backwards in csh

In bash, Ctrl + R provides the handy "search backwards" feature which isn't shipped by csh by default. If you want to use the similar function in csh, you can employ csh built-in bindkey command to implement it:

# cat .cshrc
......

bindkey "^R" i-search-back

Then you can use "search backwards" when pressing Ctrl + R:

root@FreeBSD:~ # pkg install subversion   
bck:pk

References:
Ctrl-R to search backwards for shell commands in csh.