Default file creation permissions

[Alex Zbyslaw]

Aitor San Juan wrote:

>I have a shell script whose execution is scheduled by CRON. The
>command scheduled is of the form:
>
>50 23 * * 1-5 /apps/batch/cronjobs/bd_backup.sh >
>/apps/batch/logs/bd_backup.log 2>&1
>
>This shell script runs under the id of root. The file permissions of
>the log file created are 644 (owner: root, group: wheel). I'd like that
>the file permissions of the log created be 600 (or 640 maximum). How
>could I accomplish this? This is probably related to "umask", but I
>don't dare changing anything in case that change could affect some
>other security configuration as a side effect.
>
>What would you recommend?
>  
>
One solution: write a simple wrapper shell script for this which:
    a) creates the backup.log file, deleting any existing (> backup.log 
would probably do)
    b) changes the permissions to the ones you want with chmod, chgrps 
etc. etc.
    c) runs       /apps/batch/cronjobs/bd_backup.sh >> 
/apps/batch/logs/bd_backup.log 2>&1
      I.e. appends output to the file you just blanked.

Two solution:  Always use >> in your cron job, then set up the 
backup.log to be rotated through newsyslog which can set the permissions 
correctly.  You probably need to create a balnk file with the correct 
permission once to seed the the process or use newsyslog -C.  See the 
man page for more info.


Solution one is easier, solution two also gets you a more permanent 
record of how the command ran, rather than losing it every day.

--Alex