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Full Discussion: A question about if statement
Top Forums Shell Programming and Scripting A question about if statement Post 302579185 by neutronscott on Monday 5th of December 2011 03:55:09 AM
Old 12-05-2011
[ is a command, but in bash it's a shell builtin.

Code:
$ ls -l /usr/bin/[
-rwxr-xr-x 1 root root 28300 Apr 28  2010 /usr/bin/[

Quote:
Just one last question, if [ is a command, what is its meaning in this statement if [ $i -gt $j ]
test $i greater than $j. So that exit is 0 (success) if $i > $j, and non-zero otherwise.

Since you're using bash, it's worth noting that [[ is a better and preferred test. Quoting isn't needed, and it offers more (regex matching)..

Code:
# using "[":
if [ "$i" -gt "$j" ]; then
# using bash's "[["
if [[ $i -gt $j ]]; then
# using arithmetic
if ((i > j)); then

This User Gave Thanks to neutronscott For This Post:
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LEARN ABOUT OPENSOLARIS

endusershell

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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