2 way to save a log file, what is the difference?

Shell Programming and Scripting
1

Hello good day

I would like to know what is the difference between these two commands please
both warrant the output in the file

echo " ORACLE_SID   : $ORACLE_SID"     | tee -a $logfile

echo " ORACLE_SID   : $ORACLE_SID"     > $logfile
2

The -a options of tee appends the output to the file rather than overwriting the file.

Your > $logfile code overwrites the file.

There may be more subtle differences I am not familiar with off the top of my head.

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3

tee works like a plumber's T-piece that allows gas or water flow split into two directions. tee accepts input on stdin and, on top of writing it to stdout, also writes / appends to one or several additional files. Your first version will append to a log file (create if non-existent) but also print to screen (or whatever stdout is at the time the snippet runs).

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4

Thank you very much, this information helped me a lot!