i have googled a lot,and in fabric faq also said use screen dtach with it ,but didn't find how to implement it? bellow is my wrong code,the sh will not execute as excepted it is a nohup task

def dispatch():run("cd /export/workspace/build/ && if [ -f spider-fetcher.zip ];then mv spider-fetcher.zip spider-fetcher.zip.bak;fi")put("/root/build/spider-fetcher.zip","/export/workspace/build/")run("cd /export/script/ && sh ./restartCrawl.sh && echo 'finished'")

I've managed to do it in two steps:

1. Start tmux session on remote server in detached mode:

   run("tmux new -d -s foo")

2. Send command to the detached tmux session:

   run("tmux send -t foo.0 ls ENTER")

here '-t' determines target session ('foo') and 'foo.0' tells the number of the pane the 'ls' command is to be executed in.