Date: Sun, 5 Jun 2016 22:13:20 +0200 From: Polytropon <freebsd@edvax.de> To: Baho Utot <baho-utot@columbus.rr.com> Cc: freebsd-questions@freebsd.org Subject: Re: sh[it] and What am I missing here? Message-ID: <20160605221320.ac3da346.freebsd@edvax.de> In-Reply-To: <02a5bb3c-e19a-221c-d30f-0feacebbf928@columbus.rr.com> References: <57544c10.90e58c0a.cacbc.62fd@mx.google.com> <cdf04501-79ef-9dbb-14f0-ed10a6d7241e@columbus.rr.com> <57545029.5060805@gmail.com> <6f157455-0bda-ef46-82dc-e97fb0c4a08b@columbus.rr.com> <5754550A.6020500@holgerdanske.com> <02a5bb3c-e19a-221c-d30f-0feacebbf928@columbus.rr.com>
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I'm not sure if it has been mentioned in an explicit way, so allow me to pick up some lines and clarify: On Sun, 5 Jun 2016 12:46:46 -0400, Baho Utot wrote: > login in as a user ( non root ) > set > SHELL is set to SHELL=/bin/sh > Ok now try > su - (give password) > set > SHELL=/bin/csh Ok that makes sense > Now > /bin/sh > set > SHELL=/bin/csh WTF? This is to be expected. The variable $SHELL corresponds to the "shell" field of /etc/passwd, which sets the login shell. When you use "su -", you perform a login operation, so root gets assigned the login shell as specified by /etc/passwd. Additionally, "su -" sets the environmental variables for the root user and therefore overwrites possibly different settings of the initial user; "su -m" preserves that user's environment. > login as root > set > SHELL=/bin/csh Ok that makes sense > /bin/sh > set > SHELL=/bin/csh WTF? Again, the same thing happens. If you execute /bin/sh, it will inherit the environment previously set up by /bin/csh, which also contains the $SHELL variable. Remember, $SHELL does not state which shell you are currently using - instead, it contains the name of the login shell. > It looks to me ( if I am not missing something here ) > That I can only get to sh by loging in as a user...Again WTF If you want to interactively run sh (the Bourne shell equivalent of FreeBSD, which is not a good dialog shell, but the system's default scripting shell, as well as the dialog shell for the limited maintenance mode / single user mode), just execute it. % sh # _ For scripting use, /bin/sh is recommended over bash except you really _really_ want to use bash-isms that sh does not implement. In this case, make sure your script starts with "#!/usr/local/bin/bash" (the default path after installation of bash from ports) or the more convenient "#!/usr/bin/env bash" which will also work if you force bash's install into /bin. However, you don't need to execute a shell script written for sh from inside sh. It's just important that the following conditions are met: (1st) "#!/bin/sh" is the first line, (2nd) the script is executable (use "chmod +x <name>" to set the x bit), and (3rd) the script is at a location inside $PATH, the search path from where executables are sourced. When you run csh, give the "rehash" command after you've put something into a valid executable location, or just specify the full path (use "./name" or "./name.sh" for the current directory). -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ...
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