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Full Discussion: A $(( expression )) bug?
Top Forums UNIX for Advanced & Expert Users A $(( expression )) bug? Post 302982334 by wisecracker on Wednesday 28th of September 2016 06:09:46 AM
Old 09-28-2016
It fails on ksh too!
Code:
Last login: Wed Sep 28 10:21:58 on ttys000
AMIGA:barrywalker~> ksh
AMIGA:uw> txt="1234567890"
AMIGA:uw> echo "$(( ${#txt} - 1 ))"
9
AMIGA:uw> echo "$(( #txt - 1 ))"
ksh:  #txt - 1 : arithmetic syntax error
AMIGA:uw> exit 
AMIGA:barrywalker~> _

---------- Post updated at 11:09 AM ---------- Previous update was at 10:30 AM ----------

And the WRONG answer with zsh!
Code:
AMIGA:barrywalker~> zsh
AMIGA:\u\w> zsh --version
zsh 4.3.11 (i386-apple-darwin11.0)
AMIGA:\u\w> txt="1234567890"
AMIGA:\u\w> echo "$(( ${#txt} - 1 ))"
9
AMIGA:\u\w> echo "$(( #txt - 1 ))" 
48
AMIGA:\u\w> _

EDIT:-
This should have been a new post but was added to this one, no idea why!

Last edited by wisecracker; 09-28-2016 at 07:11 AM.. Reason: See above.
 

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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/ksh93, /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/ksh93, /usr/bin/pfcsh, /usr/bin/pfksh, /usr/bin/pfsh, and /usr/bin/sh, /usr/bin/tcsh, /usr/bin/zsh, and /usr/sfw/bin/zsh. /etc/shells overrides the default list. Invalid shells in /etc/shells could cause unexpected behavior, such as being unable to log in by way of ftp(1). FILES
/etc/shells list of shells on system SEE ALSO
vipw(1B), ftpd(1M), sendmail(1M), getusershell(3C), aliases(4) SunOS 5.11 20 Nov 2007 shells(4)
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