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Output of until to file versus stdout

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# 1  
Old 03-15-2019
Output of until to file versus stdout
Why does this until false; do history | head -5; done
 result in a stdout infinite loop, yet until false; do history | head -5 > hist5; done
 only writes it once to file hist5? Furthermore, I can hear the hard drive working on the 2nd command until I end the process, but the history | head -5 is only written once.
# 2  
Old 03-15-2019
Quote:
Originally Posted by Xubuntu56
Why does this until false; do history | head -5; done
 result in a stdout infinite loop, yet until false; do history | head -5 > hist5; done
 only writes it once to file hist5? Furthermore, I can hear the hard drive working on the 2nd command until I end the process, but the history | head -5 is only written once.

It does not write once. It writes continously without break the same 5 lines into hist5 file over and over and generates considerable load at your machine. Since every session has its own history this makes no sense to do.


I'm unsure, but I assume .bash_history file is written at logout. If you want to see another sessions history with this, this will not work.
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