Bash命令連接符 | &&等
來自Stack上一篇回答Running multiple commands in one line in shell
To summarize (non-exhaustively) bash's command operators/separators:
| pipes (pipelines) the standard output (stdout) of one command into the standard input of another one. Note that stderr still goes into its default destination, whatever that happen to be.
|& pipes both stdout and stderr of one command into the standard input of another one. Very useful, available in bash version 4 and above.
&& executes the right-hand command of && only if the previous one succeeded.
|| executes the right-hand command of || only it the previous one failed.
; executes the right-hand command of ; always regardless whether the previous command succeeded or failed. Unless set -e was previously invoked, which causes bash to fail on an error.
