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Full Discussion: Evaluating a variable
Top Forums Shell Programming and Scripting Evaluating a variable Post 302459009 by mikejordan on Sunday 3rd of October 2010 07:26:26 AM
Old 10-03-2010
Evaluating a variable

Does anyone know of a way to force a variable name held in another variable to return the value of the first variable? Best if I give an example, that does not work:
Code:
/usr/local/bin >cat mike.sh
NUM1ref=16
NUM2ref=32
echo "=============="
for VAR in NUM1 NUM2
do
  XXXX=${VAR}ref
  echo $XXXX
  echo "=============="
done
/usr/local/bin >./mike.sh 
==============
NUM1ref
==============
NUM2ref
==============
/usr/local/bin >

I want this to echo the value held in NUM1ref (16), rather than the string "NUM1ref", so the variable XXXX has to be evaluated twice.

I hope that makes sense!

Last edited by Franklin52; 10-03-2010 at 10:33 AM.. Reason: Please indent your code and use code tags
 

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SYSTEMD-ACTIVATE(8)						 systemd-activate					       SYSTEMD-ACTIVATE(8)

NAME
systemd-activate - Test socket activation of daemons SYNOPSIS
/usr/lib/systemd/systemd-activate [OPTIONS...] daemon [OPTIONS...] DESCRIPTION
systemd-activate can be used to launch a socket activated daemon from the command-line for testing purposes. It can also be used to launch single instances of the daemon per connection (inetd-style). The daemon to launch and its options should be specifed after options intended for systemd-activate. If the -a option is given, file descriptor of the connection will be used as the standard input and output of the launched process. Otherwise, standard input and output will be inherited, and sockets will be passed through file descriptors 3 and higher. Sockets passed through $LISTEN_FDS to systemd-activate will be passed through to the dameon, in the original positions. Other sockets specified with --listen will use consecutive descriptors. OPTIONS
--help, -h Prints a short help text and exits. --version Prints a short version string and exits. -l address, --listen=address Listen on this address. Takes a string like "2000" or "127.0.0.1:2001". -a, --accept Launch a separate instance of daemon per connection and pass the connection socket as standard input and standard output. -E VAR[=VALUE], --environment=VAR[=VALUE] Add this variable to the environment of the launched process. If VAR is followed by "=", assume that it is a variable-value pair. Otherwise, obtain the value from the environment of systemd-activate itself. ENVIRONMENT VARIABLES
$LISTEN_FDS, $LISTEN_PID See sd_listen_fds(3). $SYSTEMD_LOG_TARGET, $SYSTEMD_LOG_LEVEL, $SYSTEMD_LOG_COLOR, $SYSTEMD_LOG_LOCATION Same as in systemd(1). EXAMPLE 1 $ /usr/lib/systemd/systemd-activate -l 2000 -a cat This runs an echo server on port 2000. EXAMPLE 2 $ /usr/lib/systemd/systemd-activate -l 19531 /usr/lib/systemd/systemd-journal-gatewayd This runs a socket activated instance of systemd-journal-gatewayd(8). SEE ALSO
systemd(1), systemd.socket(5), systemd.service(5), cat(1) systemd 208 SYSTEMD-ACTIVATE(8)
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