A slighltly better example

CHANGELOG.md

@@ -5,7 +5,7 @@ CHANGELOG
 ------
 - Added `--with-shell` option to start child processes with a custom shell command and flags
   ```sh
-  fzf --with-shell 'ruby -e' --preview 'puts {}.upcase.reverse'
+  gem list | fzf --with-shell 'ruby -e' --preview 'pp Gem::Specification.find_by_name({1})'
   ```
 - Added `change-multi` action for dynamically changing `--multi` option
     - `change-multi` - enable multi-select mode with no limit

man/man1/fzf.1

@@ -825,7 +825,7 @@ On Windows, the default value is \fBcmd /v:on/s/c\fR when \fB$SHELL\fR is not
 set.
 
 .RS
-e.g. \fBfzf --with-shell 'ruby -e' --preview 'puts {}.upcase.reverse'\fR
+e.g. \fBgem list | fzf --with-shell 'ruby -e' --preview 'pp Gem::Specification.find_by_name({1})'\fR
 .RE
 .TP
 .B "--listen[=[ADDR:]PORT]" "--listen-unsafe[=[ADDR:]PORT]"