変数
変数がなかったらデフォルト値を使う
bash の場合
foo=${HOGE:-123}
# foo = 123
bar=${HOME:-123}
# bar = /Users/userfish の場合
set -q HOGE; and set -l foo $HOGE; or set -l foo 123
# foo = 123
set -q HOME; and set -l bar $HOGE; or set -l foo 123
# bar = /Users/user都度追記
bash の場合
foo=${HOGE:-123}
# foo = 123
bar=${HOME:-123}
# bar = /Users/userfish の場合
set -q HOGE; and set -l foo $HOGE; or set -l foo 123
# foo = 123
set -q HOME; and set -l bar $HOGE; or set -l foo 123
# bar = /Users/user都度追記
