Bash question: working with an array of previously set variable strings
while i've used arrays to work with variables, i've never used them to loop through a set of strings and wanted to ask the community for some feedback or assistance.
let me be specific. here's my code:
Code:
# URL port Variables
port2195=`nc -z $url2195 2195`
port2196=`nc -z $url2196 2196`
port5223=`nc -z $url5223 5223`
port443=`nc -z $url443 443`
# Set array
range=( port2195 port2196 port5223 port443 )
echo ""
echo "Now checking the ports..."
echo ""
for i in "${range[@]}"
do
if [[ "$i" = *succeeded* ]];
then
echo "SUCCESS: $i is open/working."
else
echo "FAILURE: $i is NOT open/working."
fi
done
this code works just fine.... just not in the way that i want!
the script is passing the members of the array exactly as i've typed them, one at a time: port2195, port2196, port5223, etc.
what i'm trying to do and failing to achieve is to pass each member of the array as a previously established string: $port2195, $port2196, $port5223, etc.
changing the names of each member of the array to include a "$", doesn't work, neither does adding a second "$" into the if statement.
i'm not even sure if you can pass strings via an array but, if it is possible, much obliged for someone to drop me a few pointers.
There's at least two workarounds for that assignment statement:
Code:
- eval range=( $port2195 $port2196 $port5223 $port443 ) # deprecated as eval can be dangerous (see many a post in these fora)
- range=( $(echo $port2195 $port2196 $port5223 $port443 ))
url[2195]=foo
url[2196]=bar
url[5223]=baz
url[443]=bay
range="2195 2196 5223 443"
echo ""
echo "Now checking the ports..."
echo ""
for i in $range
do
if [[ $(nc -z "${url[i]}" $i) == *succeeded* ]];
then
echo "SUCCESS: $i is open/working."
else
echo "FAILURE: $i is NOT open/working."
fi
done
Last edited by Scrutinizer; 12-01-2014 at 06:39 PM..
if the range command (which i'd never heard of) is more effective at passing a list of values than the array command, why bother using the array command? it certainly seems like range is able to accomplish what array can do and then some.
the script works as i'd intended now, so to both of you, again: thank you.
A string with spaces is assigned to a simple variable.
Code:
for i in $range
The unquoted $range lets the shell break the string into tokens, so there is a loop over all tokens.
Of course you can directly do
Code:
for i in 2195 2196 5223 443
---------- Post updated at 04:13 AM ---------- Previous update was at 04:03 AM ----------
An alternative technique:
Code:
while read url port
do
if [[ $(nc -z "$url" "$port") == *succeeded* ]]
then
echo "SUCCESS: $port is open/working."
else
echo "FAILURE: $port is NOT open/working."
fi
done << URL_PORT
foo 2195
bar 2196
baz 5223
bay 443
URL_PORT
# Set array
range=( $port2195 $port2196 $port5223 $port443 $port25 )
If you want an array for record keeping or logging or whatever, building the array in a loop might be better...
Code:
url[2195]=localhost
url[2196]=localhost
url[5223]=localhost
url[443]=localhost
url[25]=localhost
port[2195]=""
port[2196]=""
port[5223]=""
port[443]=""
port[25]=""
echo
echo "Now checking the ports..."
echo
# fill port array in a loop
for i in ${!url[*]} # !url returns the index of the array, not the value.
do
port[$i]=$(nc -zv ${url[$i]} $i 2>&1)
if [[ ${port[$i]} =~ *succeeded* ]]; then
echo "SUCCESS: port $i is open/working."
else
echo "FAILURE: port $i is NOT open/working."
fi
done
Last edited by Scrutinizer; 12-02-2014 at 02:54 PM..
Reason: Doh! the arrow goes > that away; mod: extra code tags
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12-01-2014
Bash question: working with an array of previously set variable strings
