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Full Discussion: Creating a pseudo-array in dash, (POSIX).
Top Forums Shell Programming and Scripting Creating a pseudo-array in dash, (POSIX). Post 303028584 by Scrutinizer on Thursday 10th of January 2019 04:15:33 PM
Old 01-10-2019
How about a concept like this, mutable without eval .. :
Code:
#!/usr/local/bin/dash
set -- a b c
array() {
  _pos=$1
  _newval=$2
  _ARRAY= _i=-1 _val=
  shift 2
  for _val in "$@"
  do
    if [ $((_i+=1)) = $_pos ]; then
      _ARRAY="${_ARRAY}${_newval}
"
    else
      _ARRAY="${_ARRAY}${_val}
"
    fi
  done 
}

array 1 foo "$@"
oldIFS=$IFS
IFS="
"
set -- ${_ARRAY}

echo "Space as output field separator:
$@
"
echo "IFS as output field separator:
$*"

IFS=$oldIFS

Output:
Code:
Space as output field separator:
a foo c

IFS as output field separator:
a
foo
c

Last edited by Scrutinizer; 01-10-2019 at 05:55 PM..
These 2 Users Gave Thanks to Scrutinizer For This Post:
Chubler_XL wisecracker
 

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LEARN ABOUT DEBIAN

ndselect

NDSELECT(1)							   User Commands						       NDSELECT(1)

NAME

       ndselect - select lines and fields for numdiff

DESCRIPTION

       Usage: ndselect -h|--help|-v|--version	or

       ndselect [-b N][-e N][-s N][-F N][-L N][-I N][-S IFS][-x][-l PATH][-o PATH] [FILE]

       Print to standard output a subset of lines and fields from a given file.

       The  argument  after  the options is the name of the file to read from.	The complete path of the file should be given, a directory name is
       not accepted.  If no input file is specified, the program reads from the standard input.

       Exit status: 0 in case of normal termination, -1 (255) in case of error

       -b, --beginning, --start=N

	      Set to N the number of the first line to print (The default behavior is to start with line number 1)

       -e, --end=N

	      Set to N the number of the last line that can be printed (The default behavior is to arrive till to the end of the file)

       -s, --step=N

	      Set to N the increment to use when selecting the lines to print (The default value for the increment is 1)

       -F, --first-field=N

	      Set to N the number of the first field to print (The default behavior is to start with field number 1)

       -L, --last-field=N

	      Set to N the number of the last field that can be printed (The default behavior is to arrive till to the end of every line)

       -I, --increment=N

	      Set to N the increment to use when selecting the fields to print (The default value for the increment is 1)

       -S, --separator=IFS

	      Specify the set of characters to use to split the input lines into fields (The default set of characters is space, tab and newline).

       -x, --omit-empty-lines

	      Do not print empty lines

       -l, --warnings-to=PATH

	      Redirect warning and error messages from stderr to the indicated file

       -o, --output=PATH

	      Redirect output from stdout to the indicated file

       -h, --help

	      Show this help message

       -v, --version

	      Show version number, Copyright, Distribution Terms and NO-Warranty

COPYRIGHT

       Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012  Ivano Primi <ivprimi@libero.it>
       License GPLv3+: GNU GPL version 3 or later, see <http://gnu.org/licenses/gpl.html>.
       This is free software: you are free to change and redistribute it.  There is NO WARRANTY, to the extent permitted by law.

SEE ALSO

       The full documentation for ndselect is maintained as a Texinfo manual.  If the info and ndselect programs are properly  installed  at  your
       site, the command

	      info numdiff

       should give you access to the complete manual.

ndselect 5.6.0							   January 2012 						       NDSELECT(1)
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