perf(bash/bashrc): strip extraneous empty lines when running an alias
perf(bash/bashrc): strip extraneous empty lines when running an alias

The `apm-pkg-backup` bash alias produces some extraneous empty lines at
the bottom of the standard output. This change helps to strip those
lines.

shoichiaizawa/dotfiles,shoichiaizawa/dotfiles,shoichiaizawa/dotfiles