How to append latest output result to text file without repeating output again and again-CodePudding

I want to get job status output with latest executed time to the text file , however when I run the job each time ( schedule using cronjob ) It’s appending old, executed result also in the text file as well, but I want to get text output with latest executed result only . How to overcome this issue .

Example :

#!/bin/bash
ydate="$(date  "%H-%M-%S")"
echo "${ydate} Test1   Done " >>/app/my_status.log 2>>/app/my_status.log.err
echo "${ydate} Test2   Done " >>/app/my_status.log 2>>/app/my_status.log.err
echo "${ydate} Test3   Done " >>/app/my_status.log 2>>/app/my_status.log.err
echo "${ydate} Test4   Error " >>/app/my_status.log 2>>/app/my_status.log.err
echo "${ydate} Test5   Not_Running " >>/app/my_status.log 2>>/app/my_status.log.err

when I execute script each 5 minutes, I get result like below

14-41-14 Test1   Done
14-41-14 Test2   Done
14-41-14 Test3   Done
14-41-14 Test4   Error
14-41-14 Test5   Not_Running
14-46-15 Test1   Done
14-46-15 Test2   Done
14-46-15 Test3   Done
14-46-15 Test4   Error
14-46-15 Test5   Not_Running
14-51-15 Test1   Done
14-51-15 Test2   Done
14-51-15 Test3   Done
14-51-15 Test4   Error
14-51-15 Test5   Not_Running`

But I want to get only 5 lines with latest time like below after last execution result

14-51-15 Test1   Done
14-51-15 Test2   Done
14-51-15 Test3   Done
14-51-15 Test4   Error
14-51-15 Test5   Not_Running`

echo out the result without appending

CodePudding user response：

You want to truncate then. Use a grouping.

#!/bin/bash

ydate=$(date  "%H-%M-%S")

{
    echo "${ydate} Test1   Done"
    echo "${ydate} Test2   Done"
    echo "${ydate} Test3   Done"
    echo "${ydate} Test4   Error"
    echo "${ydate} Test5   Not_Running"
} >/app/my_status.log 2>/app/my_status.log.err

You can also use exec to open a file and use a file descriptor for the whole session. Just look around for examples.