1

Trying bash shell scripting and running into small issue:

# hostname --short
7phdsn01
# virsh --readonly list --state-running --name
Nagios

# set $(hostname --short)=$(virsh --readonly list --state-running --name)
# echo $?
0
# echo $7phdsn01
phdsn01
# 

Please advise.


# unset $7phdsn01
# set $(hostname --short)=$(virsh --readonly list --state-running --name)
# echo $7phdsn01
phdsn01
# 
  • @MichaelHomer please see my updated question with output for your comment. – alexus Jun 11 '19 at 19:55
  • Your set $(hostname ...)=$(virsh ...) will just set $1 (the 1st positional parameter) to the 7phdsn01=Nagios string and will succeed, that's why you get $? = 0. – mosvy Jun 11 '19 at 20:23
2

The set command does not set values of shell variables like that in bash. You may want to try with declare instead.

It looks as if you want to use a variable named after the hostname. Unfortunately, the hostname starts with a digit, so it can't be used as the name of a variable.

The command echo $7phdsn01 outputs phdsn01 since $7 (the 7th positional parameter) is unset and expands to nothing, followed by the rest of the string.

I would probably have used

declare -A state

state["$(hostname --short)"]=$(virsh --readonly list --state-running --name)

This would create an associative array called state. The next line sets the value for the key given by the hostname --state command to the output of the virsh command.

The values and keys of the state array could then be had like this:

for host in "${!state[@]}"; do
    printf 'Host %s is in state %s\n' "$host" "${state[$host]}"
done

If you're doing this for a single host, then obviously there is no need to be that fancy. Instead just use two variables:

host=$(hostname --short)
state=$(virsh --readonly list --state-running --name)

printf 'Host %s is in state %s\n' "$host" "$state"
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