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Full Discussion: Bash not equal string comparison
Top Forums Shell Programming and Scripting Bash not equal string comparison Post 302920410 by RavinderSingh13 on Thursday 9th of October 2014 10:04:35 AM
Old 10-09-2014
Quote:
Originally Posted by cokedude
Why does this cause an infinite loop?

Code:
#!/bin/bash
 
 
while [[ "$(ipcs | awk '{print $2}')" != "Semaphore" ]]; do
    echo "$(ipcs | awk '{print $2}')"
 
done
 
echo 
exit 0

I have verified I eventually get Semaphore so it should break out of the while loop.

Code:
$ echo $(ipcs | awk '{print $2}')
Shared shmid 262145 294914 2326531 Semaphore semid Message msqid

Hi cokedude,
Could you please try following.

Code:
while [[ "$(ipcs | awk '{print $2}')" !~ "Semaphore" ]]; do
    echo "$(ipcs | awk '{print $2}')" 
done 
echo 
exit 0

Thanks,
R. Singh
 

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LEARN ABOUT SUNOS

shells

shells(4)							   File Formats 							 shells(4)

NAME

       shells - shell database

SYNOPSIS

       /etc/shells

DESCRIPTION

       The shells file contains a list of the shells on the system. Applications use this file to determine whether a shell is valid. See getuser-
       shell(3C). For each shell a single line should be present, consisting of the shell's path, relative to root.

       A hash mark (#) indicates the beginning of a comment; subsequent characters up to the end of the line are not interpreted by  the  routines
       which search the file. Blank lines are also ignored.

       The  following  default	shells are used by utilities: /bin/bash, /bin/csh, /bin/jsh, /bin/ksh, /bin/pfcsh, /bin/pfksh, /bin/pfsh, /bin/sh,
       /bin/tcsh,  /bin/zsh,  /sbin/jsh,  /sbin/sh,  /usr/bin/bash,  /usr/bin/csh,  /usr/bin/jsh,  /usr/bin/ksh,  /usr/bin/pfcsh,  /usr/bin/pfksh,
       /usr/bin/pfsh, and /usr/bin/sh, /usr/bin/tcsh, /usr/bin/zsh. Note that /etc/shells overrides the default list.

       Invalid shells in /etc/shells may cause unexpected behavior (such as being unable to log in by way of ftp(1)).

FILES

       /etc/shells	       lists shells on system

SEE ALSO

       vipw(1B), ftpd(1M), sendmail(1M), getusershell(3C), aliases(4)

SunOS 5.10							    4 Jun 2001								 shells(4)
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