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Top Forums Shell Programming and Scripting Extracting unknown positional parameter in Bourne shell Post 302597910 by Scrutinizer on Monday 13th of February 2012 12:17:55 AM
Old 02-13-2012
You're welcome. Yes, also in Shell one should think twice before using eval in certain situations, so that it does not leave a security hole. Those curly brackets are important in this case BTW. If you leave them out then if the parameter would become $10 for example, that would get evaluated to $1 with a trailing zero, whereas ${10} would give the right result.

Last edited by Scrutinizer; 02-13-2012 at 01:24 AM..
 

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shift(1)							   User Commands							  shift(1)

NAME
shift - shell built-in function to traverse either a shell's argument list or a list of field-separated words SYNOPSIS
sh shift [n] csh shift [variable] ksh * shift [n] DESCRIPTION
sh The positional parameters from $n+1 ... are renamed $1 ... . If n is not given, it is assumed to be 1. csh The components of argv, or variable, if supplied, are shifted to the left, discarding the first component. It is an error for the variable not to be set or to have a null value. ksh The positional parameters from $n+1 $n+1 ... are renamed $1 ..., default n is 1. The parameter n can be any arithmetic expression that evaluates to a non-negative number less than or equal to $#. On this man page, ksh(1) commands that are preceded by one or two * (asterisks) are treated specially in the following ways: 1. Variable assignment lists preceding the command remain in effect when the command completes. 2. I/O redirections are processed after variable assignments. 3. Errors cause a script that contains them to abort. 4. Words, following a command preceded by ** that are in the format of a variable assignment, are expanded with the same rules as a vari- able assignment. This means that tilde substitution is performed after the = sign and word splitting and file name generation are not performed. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Availability |SUNWcsu | +-----------------------------+-----------------------------+ SEE ALSO
csh(1), ksh(1), sh(1), attributes(5) SunOS 5.10 15 Apr 1994 shift(1)
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