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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 MOJAVE

qmail-getpw

qmail-getpw(8)						      System Manager's Manual						    qmail-getpw(8)

NAME

       qmail-getpw - give addresses to users

SYNOPSIS

       qmail-getpw local

DESCRIPTION

       In  qmail,  each  user controls a vast array of local addresses.  qmail-getpw finds the user that controls a particular address, local.	It
       prints six pieces of information, each terminated by NUL: user; uid; gid; homedir; dash; and ext.  The user's account  name  is	user;  the
       user's  uid  and  gid  in  decimal  are	uid  and gid; the user's home directory is homedir; and messages to local will be handled by home-
       dir/.qmaildashext.

       In case of trouble, qmail-getpw exits nonzero without printing anything.

       WARNING: The operating system's getpwnam function, which is at the heart of qmail-getpw, is inherently unreliable: it fails to  distinguish
       between	temporary  errors and nonexistent users.  Future versions of getpwnam should return ETXTBSY to indicate temporary errors and ESRCH
       to indicate nonexistent users.

RULES

       qmail-getpw considers an account in /etc/passwd to be a user if (1) the account has a nonzero uid, (2) the account's home directory  exists
       (and  is visible to qmail-getpw), and (3) the account owns its home directory.  qmail-getpw ignores account names containing uppercase let-
       ters.  qmail-getpw also assumes that all account names are shorter than 32 characters.

       qmail-getpw gives each user control over the basic user address and all addresses of the form user-anything.  When local is user, dash  and
       ext  are  both  empty.  When local is user-anything, dash is a hyphen and ext is anything.  user may appear in any combination of uppercase
       and lowercase letters at the front of local.

       A catch-all user, alias, controls all other addresses.  In this case ext is local and dash is a hyphen.

       You can override all of qmail-getpw's decisions with the qmail-users mechanism, which is reliable, highly  configurable,  and  much  faster
       than qmail-getpw.

SEE ALSO

       qmail-users(5), qmail-lspawn(8)

																    qmail-getpw(8)
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