Scalar variables in Perl are always referenced with the leading $. In the shell, you use $ to get the value, but leave the $ off to assign a new value. In awk or C, you leave the $ off entirely. If you bounce back and forth a lot, you’ll find yourself typing the wrong things occasionally. This is expected.
这段话引自Learning Perl第三版 2.5 Scalar Variables。我就遇到过这种情况,当时非常具有挫败感,一种暗无天日、没有前途的感觉。看了这段话,心理舒服多了,正常嘛,大家都这样,并非我个人的问题。
就我看来,This is expected
这句话的价值非常大,它让人不必在无谓(或者无法控制)的事情上浪费感情。