topic Re: how to reduce a large file in Operating System - HP-UX

how to reduce a large file

Ignacio Rodríguez Arrós — Fri, 02 Aug 2002 05:57:52 GMT

I have a 55Mg file in oracle (alert_baan.log) and i want to reduce it by supressing the 1000000 first lines.Witch command must i used?
(Sorry for my english, i hope you'll understand it)

Re: how to reduce a large file

Steve Steel — Fri, 02 Aug 2002 06:06:06 GMT

Hi

Copy it to another name and then use
tail +n 1000001 newfile > oldfile
rm newfile

see man tail

Steve Steel

Re: how to reduce a large file

Pierce Byrne_1 — Fri, 02 Aug 2002 06:07:18 GMT

tail +100000 file > file.new
mv file.new file

Re: how to reduce a large file

Stefan Farrelly — Fri, 02 Aug 2002 06:09:32 GMT

The alert log is constantly being help open/possibly written to so I dont think you want to rm it. Simply null it out by doing;
cat /dev/null >alert_baan.log

This will make the logfile 0 bytes in size but not remove it so that any running processes using this logfile can still use it.

Re: how to reduce a large file

Ravi_8 — Fri, 02 Aug 2002 06:24:37 GMT

Hi

#tail +n 1000000 file > newfile
#mv newfile file

should do the job

Re: how to reduce a large file

James Beamish-White — Fri, 02 Aug 2002 06:31:03 GMT

Hiya,

Yes, the commands (as stated above) are:

tail +1000000 alert_baan.log > myfile
mv myfile alert_baan.log

I would put it in a script so as to minimise the time between commands, otherwise you might overwrite some logs that are added to the end of the original file before you mv the new file over it.

Cheers!
James

Re: how to reduce a large file

Kenneth_19 — Fri, 02 Aug 2002 06:36:51 GMT

This method also works:

# sed -n '1000000,$ p' alert_baan.log > new_file
# mv new_file alert_baan.log

Regards,
Kenneth

Re: how to reduce a large file

Justo Exposito — Fri, 02 Aug 2002 06:43:25 GMT

Hi Ignacio,

You can do it by using ed, in order to do it try this:
echo "1, 1000000 d\nw" | ed alert_baan.log

Hope this helps you,

Justo.

Deber??as adjudicar puntos a las soluciones que te dan, esas son las reglas y recomendaciones del foro y si no lo haces podr??as dejar de obtener ayuda.

Re: how to reduce a large file

Bill McNAMARA_1 — Fri, 02 Aug 2002 06:46:52 GMT

split has a line option also, and can be useful for large file operations..

Later,
Bill

Re: how to reduce a large file

Ignacio Rodríguez Arrós — Fri, 02 Aug 2002 07:07:16 GMT

Justo, he entrado a ver las respuestas 4 veces y las cuatro veces he asignado puntos, luego pincho en submit, espero a que salga la siguiente pantalla y cierro el explorador, pero he observado que cuando vuelvo a entrar, los punto no aparecen, sigue a pareciendo el boton para asignarlos. Lo siento pero no se lo que hago mal para que no aparezcan. Si me indicais c??mo hacerlo correctamente vuelvo a a signarlos. A Y gracias a todos, todas las soluciones son validas aunque he usado la de cat /dev/nul >

Re: how to reduce a large file

Nick Wickens — Fri, 02 Aug 2002 07:47:04 GMT

I use csplit to housekeep log files - Attached is a script I use which maintains only the last few weeks of my aplications log directories. Because the application does not write a regular datestamp in the log I force one by running this everynight at midnight.

ERRORLOG=/opt/ROBIN/log
for LOGNAME in $(ls $ERRORLOG | grep rerr)
do
date +Logday=%.1j >> $ERRORLOG/$LOGNAME
done

The script attached is then run 30 minutes later.

Re: how to reduce a large file

Nick Wickens — Fri, 02 Aug 2002 07:51:40 GMT

Translation courtesy of altavista

Just, I have entered to see the answers 4 times and the four times I have assigned points, soon thorn in submit, hope to that it leaves the following screen and I close the explorer, but have observed that when I return to enter, them point do not appear, follows seeming the button to assign them. I feel it but not what I make bad so that they do not appear. If me indicais how to do it correctly I return to a to sign them. To and thanks to all, all the solutions are been worth although I have used the one of cat/dev/nul >

Re: how to reduce a large file

Nick Wickens — Fri, 02 Aug 2002 07:54:19 GMT

Heres the script that failed to attach earlier (hopefully !)

Re: how to reduce a large file

Nick Wickens — Fri, 02 Aug 2002 08:03:03 GMT

Ok third time lucky - heres the script (please please please appear this time !)