stderr redirection

[zyrag]

hi, how do i redirect stderr to a log file and at the same time display the error message at the console?

This is the first time i work with scripting. Part of my script below worked to redirect the error message but to display the same at the console is what i don't know how.

tar -cvf /dev/rmt0 /file1 /file2 2>> backup.log

Also, how will i trap if an error exists so i could have and If-Then-Else statement to display successful or unsuccessful backup?

thanks,

 

[mokano]

You can use tee command to display output of a program and copies into a file, look at:

http://www16.boulder.ibm.com/pseries/en_US/cmds/aixcmds5/tee.htm

Use the variable $? in shell script, it shows if executed command was ok or not.

Regards,

Okano

 

[zyrag]

thanks mokano, it works great. but, if i only want to log the associated errors, how will i do it?

Also, how will i know if a tape media has been inserted or not into the tape drive?

thanks again.

 

[dblair]

Use the mt command to check for media.
eg, mt -f /dev/rmt0 rewind

 

[nAtHaNs]

zyrag,

use

tar -cvf /dev/rmt0 /file1 /file2 >> backup.log 2>&1

 

[zyrag]

thanks nathans for your help. I think i should continue using the command `tar -cvf /dir 2>>$HOME/backup.log` so that only the errors are logged and yet retaining the ouput to be displayed at the console. The user won't understand anyway about the errros that might occur.