Re: A "Where am I" routine

[David Christensen <dpchrist@holgerdanske.com>]

On 07/06/18 07:00, Richard Owlett wrote:
> On 07/06/2018 07:15 AM, Zenaan Harkness wrote:
> > On Fri, Jul 06, 2018 at 06:25:43AM -0500, Richard Owlett wrote:
> > > I multi-boot several configurations &/or releases of Debian.
> > > I will run identical test scripts on each.
> > > I want to store the results in a common logging file.
> > >
> > > I can set up an appropriate environment with a custom fstab containing:
> > > >   # create a common area
> > > >   LABEL=owlcommon /home/richard/Documents/tst_common vfat 
> > > > user,rw,umask=000 0 0
> > > >   # a dummy mount labeled to show which instance
> > > >   LABEL=dummy /home/richard/Documents/where/sda14 ext4 user,ro 0 0
> > > The first statement gives me a directory usable by all.
> > > The second tells me where I am by using:
> > >     ls /home/richard/Documents/where
> > > in any test script.

> As I've only one machine, I'm never conscious of it having a host name.
> When I do a new install the same string is generally used for both the 
> host name and the partition label - generally a reminder of current 
> purpose.
>
> E.G.
> hostname returns "debian-jan13" -- when installed was key information
> Partition label is "new-net-inst" -- I didn't install from DVD.
> The partition is /dev/sda14 .
> Desired information dependent on topic-du-jour.

One file and two commands come to mind:

2018-07-06 18:55:59 dpchrist@po ~
$ cat /etc/debian_version
9.4

2018-07-06 19:07:38 dpchrist@po ~
$ uname -a
Linux po 4.9.0-6-amd64 #1 SMP Debian 4.9.88-1+deb9u1 (2018-05-07) x86_64 
GNU/Linux

2018-07-06 19:25:55 dpchrist@po ~/sandbox/debian
$ mount -l | grep 'on / '
/dev/mapper/sda3_crypt on / type btrfs 
(rw,relatime,ssd,space_cache,subvolid=5,subvol=/) [po_root]


In a shell script, you can assign these values into variables:

2018-07-06 19:29:15 dpchrist@po ~/sandbox/debian
$ cat id_debian
#!/bin/sh
# $Id: id_debian,v 1.3 2018/07/07 02:30:11 dpchrist Exp $
# Simple-minded script for identifying Debian hosts
# Copyright 2018 by David Paul Christensen dpchrist@holgerdanske.com
# Public domain

DEBIAN_VERSION=`/bin/cat /etc/debian_version`
UNAME_A=`/bin/uname -a`
MOUNT_L_ROOT=`/bin/mount -l | /bin/grep 'on / '`

2018-07-06 19:30:16 dpchrist@po ~/sandbox/debian
$ /bin/sh id_debian


You can source the above script from another script to obtain the 
variable values:

2018-07-06 19:32:08 dpchrist@po ~/sandbox/debian
$ cat source_id_debian
#!/bin/sh
# $Id: source_id_debian,v 1.2 2018/07/07 02:32:07 dpchrist Exp $
# Sources 'id_debian' to obtain identification variables
# Copyright 2018 by David Paul Christensen dpchrist@holgerdanske.com
# Public domain

. ./id_debian

echo $DEBIAN_VERSION
echo $UNAME_A
echo $MOUNT_L_ROOT

2018-07-06 19:32:10 dpchrist@po ~/sandbox/debian
$ /bin/sh source_id_debian
9.4
Linux po 4.9.0-6-amd64 #1 SMP Debian 4.9.88-1+deb9u1 (2018-05-07) x86_64 
GNU/Linux
/dev/mapper/sda3_crypt on / type btrfs 
(rw,relatime,ssd,space_cache,subvolid=5,subvol=/) [po_root]


David