07-30-2013
Significance of different shells?
I'm taking a LINUX and UNIX class and we are using bash as the shell in terminal. On my mac-book I use zsh only because my professor had a pretty cool start-up file for it.
It has benefited me in becoming familiar with different shells. However, I'm having a hard time understanding the purpose of the shell and why there are so many shells out there and the importance or instance of using one over the other.
I understand zsh is very powerful. However, I see the same with bash. I wrote a few simple scripts in bash as well as zsh and see that they are very familiar in syntax. I've also found out that it doesn't matter what shell I'm in when I want to run a script.
For example, #!/bin/bash, stating this in the top of my bash script still allows me to run it in zsh.
It also seems that no matter what shell your currently in the commands at the command line are always the same as far as navigating around.
Therefore, what's the purpose of the shell and instances/advantages of using one over the over?
Last edited by syregnar86; 07-30-2013 at 04:59 PM..
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LEARN ABOUT SUNOS
getusershell
getusershell(3C) Standard C Library Functions getusershell(3C)
NAME
getusershell, setusershell, endusershell - get legal user shells
SYNOPSIS
#include <unistd.h>
char *getusershell(void);
void setusershell(void);
void endusershell(void);
DESCRIPTION
The getusershell() function returns a pointer to a legal user shell as defined by the system manager in the file /etc/shells. If
/etc/shells does not exist, the following locations of the standard system shells are used in its place:
/bin/bash /bin/csh
/bin/jsh /bin/ksh
/bin/pfcsh /bin/pfksh
/bin/pfsh /bin/sh
/bin/tcsh /bin/zsh
/sbin/jsh /sbin/pfsh
/sbin/sh /usr/bin/bash
/usr/bin/csh /usr/bin/jsh
/usr/bin/ksh /usr/bin/pfcsh
/usr/bin/pfksh /usr/bin/pfsh
/usr/bin/sh /usr/bin/tcsh
/usr/bin/zsh /usr/xpg4/bin/sh
The getusershell() function opens the file /etc/shells, if it exists, and returns the next entry in the list of shells.
The setusershell() function rewinds the file or the list.
The endusershell() function closes the file, frees any memory used by getusershell() and setusershell(), and rewinds the file /etc/shells.
RETURN VALUES
The getusershell() function returns a null pointer on EOF.
BUGS
All information is contained in memory that may be freed with a call to endusershell(), so it must be copied if it is to be saved.
SunOS 5.10 30 Aug 2004 getusershell(3C)