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Full Discussion: Bash Variable scope - while loop while reading from a file
Top Forums UNIX for Beginners Questions & Answers Bash Variable scope - while loop while reading from a file Post 303037381 by bakunin on Wednesday 31st of July 2019 02:39:50 AM
Old 07-31-2019
Quote:
Originally Posted by wisecracker
As is often the case with a little bit of jiggery pokery there is a pseudo-back-door.
This is especially for you:

Code:
#! /bin/bash

pInitPermStor ()
{
if [ ! -d "$fStorage" ] ; then
     return $(mkdir -p "$fStorage")            # create storage dir if not there
fi

return $(rm -f "$fStorage/*")                  # empty it if it already exists
}




pRemovePermStor ()
{
if [ ! -d "$fStorage" ] ; then
     return 1                                  # shouldn't happen
fi

return $(rm -f "$fStorage")                    # clean up
}




pGetVar ()
{
local chVar="$1"

if [ -f "${fStorage}/${chVar}" ] ; then
     printf "%s=%s\n" "$chVar" $( < "${fStorage}/${chVar}" )
else
     printf "$chVar"=\"\"
fi

return 0
}


pPutVar ()
{
local chVar="$1"
local chValue="$2"

if ! printf "%s\n" "$2" > "${fStorage}/${chVar}" ; then
     return 1
fi

return 0
}


# ------------------ main()
declare fStorage="/path/to/dir/$$"

if ! pInitPermStor ; then
     printf "ERROR: cannot initialise permanent variable storage\n" >&2
     exit 1
fi

pPutVar "x" "abcd"             # set value of variable x to "abcd"
eval $( pGetVar "x" )          # retrieve and set variable x
echo var x is: $x

if ! pRemovePermStor ; then
     printf "ERROR: permanent variable storage not found\n" >&2
     exit 1
fi
exit 0

ROFL, i doubt this helps anyone but it was fun to write.

bakunin

/edited following MadeInGermanys suggestion
Last edited by bakunin; 07-31-2019 at 10:19 AM..
 

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LEARN ABOUT REDHAT

printf

PRINTF(1)								FSF								 PRINTF(1)

NAME

       printf - format and print data

SYNOPSIS

       printf FORMAT [ARGUMENT]...
       printf OPTION

DESCRIPTION

       NOTE:  your shell may have its own version of printf which will supercede the version described here. Please refer to your shell's documen-
       tation for details about the options it supports.

       Print ARGUMENT(s) according to FORMAT.

       --help display this help and exit

       --version
	      output version information and exit

       FORMAT controls the output as in C printf.  Interpreted sequences are:

       "     double quote

       NNN  character with octal value NNN (0 to 3 digits)

       \     backslash

       a     alert (BEL)

            backspace

       c     produce no further output

       f     form feed

       
     new line

       
     carriage return

       	     horizontal tab

       v     vertical tab

       xNNN  byte with hexadecimal value NNN (1 to 3 digits)

       uNNNN character with hexadecimal value NNNN (4 digits)

       UNNNNNNNN
	      character with hexadecimal value NNNNNNNN (8 digits)

       %%     a single %

       %b     ARGUMENT as a string with `' escapes interpreted

       and all C format specifications ending with one of diouxXfeEgGcs, with ARGUMENTs converted to proper type first.  Variable widths are  han-
       dled.

AUTHOR

       Written by David MacKenzie.

REPORTING BUGS

       Report bugs to <bug-coreutils@gnu.org>.

COPYRIGHT

       Copyright (C) 2002 Free Software Foundation, Inc.
       This is free software; see the source for copying conditions.  There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICU-
       LAR PURPOSE.

SEE ALSO

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

	      info printf

       should give you access to the complete manual.

GNU coreutils 4.5.3						   February 2003							 PRINTF(1)
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