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Full Discussion: Not able to understand IFS
Top Forums Shell Programming and Scripting Not able to understand IFS Post 302764811 by scriptor on Friday 1st of February 2013 03:00:24 AM
Old 02-01-2013
Not able to understand IFS

Hi ,

i am in my initial learning phase of unix. i was going thru the function part.
below is the example which was there but i am not able to understand logic and the use of IFS(internal field separator)

Code:
lspath() {
OLDIFS="$IFS"
IFS=:
for DIR in $PATH ; do echo $DIR ; done
IFS="$OLDIFS"
}

the output is below. here i am failed to understand how the o/p is coming like below
and logic behind the IFS.

Code:
/sbin
/bin
/usr/bin
/usr/sbin
/opt/bin
/usr/ucb
/usr/ccs/bin
/usr/openwin/bin

regards,
scriptor
 

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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)
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