[CentOS] logrotate, syslog, and chsh

Sun Mar 11 13:49:24 UTC 2007
Will McDonald <wmcdonald at gmail.com>

On 11/03/07, Jeff Potter <jpotter-centos at codepuppy.com> wrote:
> I'm noticing that logrotate's default configuration for rotating /var/
> log/secure and /var/log/messages partially fails if root's shell is
> set to /bin/tcsh (via chsh).  (Running on CentOS 4.4;
> logrotate-3.7.1-5.RHEL4).
> What seems to be happening is that the logrotate.d/syslog postrotate
> command runs:
>         /bin/kill -HUP `cat /var/run/syslogd.pid 2> /dev/null` 2> /dev/null
> || true
> Under bash, this redirects stderr to /dev/null. Under tcsh, this
> produces the error:
>         cat: 2: No such file or directory
> What happens in this scenario is that the log gets rotated, but
> syslogd does not receive the SIGHUP, so nothing gets logged, at all.
> (i.e. secure and messages are 0 bytes until syslog is kicked).
> I'm just going to set the default shell for root back to bash, but I
> wanted to ask the list if there is any general "rule of thumb" that
> root's shell should be bash?

Across most Unixes I think it's a given that root's shell is just
'sh', either /bin/sh or /sbin/sh. On Solaris a commonly warned against
mistake was to either change root's shell to a dynamically linked
shell which wouldn't work properly in single-user because of linked
libraries residing on unmounted partition (only / was mounted in
single user mode IIRC) or because it was /usr/local/bin/bash, again
with /usr/ not residing in a directory under / .

You can set SHELL=/bin/bash in crontabs to override a user's default
shell. See "man 5 crontab" for details.

Your error is being caused by limitations in csh's handling of
standard file descriptors, explained here: