03-27-2001
Quote:
what is the noclobber variable? what does it do?
If you turn on the noclobber option with "set noclobber" then redirecting to an existing file using the > should produce an error. In csh/tcsh this can be overridden on a case-by-case basis with >!, in bash/ksh it is >|
In csh/tcsh you also have the >>! syntax. If noclobber is set, and you use >> to append to a file, you will get an error if the file does <I>not exist</I> (can't append to a non-existant file). If you use >>! you will override this behaviour, and create the file if it does not already exist. I dont believe that bash or ksh have this feature (file is always created if it does not exist).
noclobber is a handy option if you tend to frequently overwrite files that you intended to keep. See the relevant manual page for your shell to learn more about this and other options.
[Edited by PxT on 03-27-2001 at 12:34 AM]
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LEARN ABOUT OPENSOLARIS
setusershell
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/ksh93 /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/ksh93 /usr/bin/pfcsh
/usr/bin/pfksh /usr/bin/pfsh
/usr/bin/sh /usr/bin/tcsh
/usr/bin/zsh /usr/sfw/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.
NOTES
Restricted shells should not be listed in /etc/shells.
SunOS 5.11 1 Nov 2007 getusershell(3C)