Shell Programming and Scripting

Hey Guys,

I was wondering if someone would give me a hand with an issue I'm having, let me explain the situation:

I have a file that is constantly being written to and read from with updated lines:

# cat activity.file
activity1
activity2
activity3
activity4
activity5

This file should never have more than 60 lines of text, so the "writing" process is as follows:

# tail -59 activity.file > temp; mv temp activity.file; echo "activityN" >> activity.file

Basically what this does is:

1.- Gets the bottom 59 files of activity.file into a temp file
2.- Renames the temp file into the original filename ( activity.file )
3.- Appends the new data in the bottom of the activity file.

So far this works great, but I'm trying to find a way to do the same procedure but without utilizing a temp file, as a "one-liner" as they say..

I tried the following:

tail -59 activity.file > activity.file ; echo "activityN" >> activity.file

But that didn't work...

Any ideas would be greatly appreciated

Thanks

Code:

FILE=`tail -n 59 activity.file`; echo "$FILE" > activity.file ; echo "activityN" >> activity.file

thank you so much i think that did it