nohup的使用

nohup 的用途就是讓提交的命令忽略 hangup 信號。讓咱們先來看一下 nohup 的幫助信息

NOHUP(1)                  BSD General Commands Manual                 NOHUP(1)

NAME
     nohup -- invoke a utility immune to hangups

SYNOPSIS
     nohup [--] utility [arguments]

DESCRIPTION
     The nohup utility invokes utility with its arguments and at this time sets the signal SIGHUP to be ignored.  If the
     standard output is a terminal, the standard output is appended to the file nohup.out in the current directory.  If stan-
     dard error is a terminal, it is directed to the same place as the standard output.

     Some shells may provide a builtin nohup command which is similar or identical to this utility.  Consult the builtin(1)
     manual page.

可見，nohup 的使用是十分方便的，只需在要處理的命令前加上 nohup 便可，標準輸出和標準錯誤缺省會被重定向到 nohup.out 文件中。通常咱們可在結尾加上"&"來將命令同時放入後臺運行，也可用">filename 2>&1"來更改缺省的重定向文件名。

Lawrences-MBP:~ Lawrence$ nohup python test.py &

另外，python在print時，有時會等待緩衝區滿了纔打印數據，這時使用 python -u 能夠強制stdin，stdout和stderr變成無緩衝，當即輸出。