Bjgirl few questions to ask? Thank you First, N one of the final shows how recycling firms Secondly, Starting at the specified time in a one-hour operation procedures do not crontab, only shell Thirdly, How real-time monitoring of a certain document, the contents have appeared to return to the information Want to detail, I would like to thank first! Bjgirl few questions to ask? Thank you 1, [code]while true;do tail -nN file;done[/code] 2,3, and while+sleep to achieve, the more general problem : oops : Bjgirl few questions to ask? Thank you 1. Tail-f file -n20 Bjgirl few questions to ask? Thank you Second, such as the daily operation of the shell at 5:00 to complete the function of the shell can cycle time to judge whether the current system at 5:00 Thirdly, such as a text document, he was uncertain when the shell operation, check text documents, which emerged as "operational error" and so on the specified information, shell is a piece of information given to the export terminal. I wonder if there is clear, thank you Bjgirl few questions to ask? Thank you --> [code] Time= "5:00" While true;do [[($ Date +%k:%M) -eq $Time Says sleep, named cmd | | N Done[/code] --> [code]while True;do Grep-q "operational error", named echo text messages sleep N | | Done[/code] Thinking so broadly, the code without tests. : Oops : Bjgirl few questions to ask? Thank you Very grateful that a problem is a cycle running in the background but I should warn that the end can kill, but when the cycle of nest kill but I should warn ineffective For example : Trap "kill Private consumption expenditure" 1 2 15 While [1] Do Show menu. . . Read choice $choice In case 1) ....... 2) (while [1] Do Tail -n10 abcd.txt Done) & Read key Private consumption expenditure kill Esac Done Cycle that can kill the background, what is the reason? Bjgirl few questions to ask? Thank you [code] While true;do Grep-q "operational error", named echo text messages sleep N | | Done [/code] I think this solution is slow if the file is big. Make a named pipe is a good idea. Your script read the pipe, check string and write to the real file. Bjgirl few questions to ask? Thank you Ding [ Closed window ]