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Full Discussion: Variable within variable expansion
Top Forums Shell Programming and Scripting Variable within variable expansion Post 303044728 by hburnswell on Monday 2nd of March 2020 04:15:37 PM
Old 03-02-2020
Variable within variable expansion
Hi,

I have been trying to get variable within variable expansion to work but have not been able to succeed. It seems that the two suggestions I am seeing are using 'eval' and using the built in bash capability of "${!test}". Here is a snippet of what I"m trying to accomplish:

Code:
#!/bin/bash
b2b_qa_site=1234
b2c_qa_site=4321
b2b_prd_site=5678
b2c_prd_site=8765

grp=`echo "${1: -2:1}"`
env=`echo "${1: -3:1}"`


if [[ $env -eq 4 ]]; then

        env=prd

else

        env=qa

fi

if [[ $grp -eq 0 ]]; then

        grp=b2b

else

        grp=b2c

fi

test=${grp}_${env}_site
eval echo \$test

This would be used as:

Code:
# ./script box400

And ideally receive:

Code:
5678

Can anyone shed some light on what I am doing wrong here? I appreciate any guidance.

Thanks,
HB
 

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LEARN ABOUT POSIX

grp.h

<grp.h>(P)						     POSIX Programmer's Manual							<grp.h>(P)

NAME

       grp.h - group structure

SYNOPSIS

       #include <grp.h>

DESCRIPTION

       The <grp.h> header shall declare the structure group which shall include the following members:

	      char   *gr_name The name of the group.
	      gid_t   gr_gid  Numerical group ID.
	      char  **gr_mem  Pointer to a null-terminated array of character
			      pointers to member names.

       The gid_t type shall be defined as described in <sys/types.h> .

       The following shall be declared as functions and may also be defined as macros. Function prototypes shall be provided.

	      struct group  *getgrgid(gid_t);
	      struct group  *getgrnam(const char *);

	      int	     getgrgid_r(gid_t, struct group *, char *,
				 size_t, struct group **);
	      int	     getgrnam_r(const char *, struct group *, char *,
				 size_t , struct group **);

	      struct group  *getgrent(void);
	      void	     endgrent(void);
	      void	     setgrent(void);

       The following sections are informative.

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       <sys/types.h> , the System Interfaces volume of IEEE Std 1003.1-2001, endgrent(), getgrgid(), getgrnam()

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
       ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
       Electrical  and	Electronics  Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE
       and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can  be  obtained
       online at http://www.opengroup.org/unix/online.html .

IEEE
/The Open Group						       2003								<grp.h>(P)
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