如何从命令变量在bash中创建数组？

Question

I'm trying to get an SNMP walk into an array, the data in the variable is in the format "data1 data2" "data3 data4" . Essentially I just want the data between the double quotes, regardless of how many spaces there may be.

I've been googleing for about an hour and a half and cannot figure out how to get the array correctly formatted.

Here is a snippit of the code that I have right now...

IN=$(snmpwalk -Oqv -v2c -c$community $ipaddr .1.3.6.1.4.1.32050.2.1.26.2)
portdesc=($(echo $IN))

This does put it in an array, but when trying to access the first data set I get "data1 instead of "data1 data2" . I can cheat and just use two variables but I'd rather do it the right way and just reference the array for the item that I want. If you can help me with this I will be eternally greatfull.

echo "DEBUG0: ${portdesc[@]}"
echo "DEBUG1: ${portdesc[0]}"

DEBUG0: "Relay Output" "Expansion Power" "Expansion Tripped" "Switch Input" "Radio 1 Power" "Radio 2 Power" "Radio 3 Power" "Radio 4 Power" "Radio 1 Sync" "Radio 2 Sync" "Radio 3 Sync" "Radio 4 Sync" "Radio 1 Tripped" "Radio 2 Tripped" "Radio 3 Tripped" "Radio 4 Tripped" "SyncPipe Power" "SyncPipe Tripped" "Switch to NMEA" "2D Fix" "3D Fix" "DGPS Fix" "1PPS Active" "Radio 1 Power" "Radio 2 Power" "Radio 3 Power" "Radio 4 Power" "Radio 1 Sync" "Radio 2 Sync" "Radio 3 Sync" "Radio 4 Sync" "Radio 1 Tripped" "Radio 2 Tripped" "Radio 3 Tripped" "Radio 4 Tripped" "SyncPipe Power" "SyncPipe Tripped" "Switch to NMEA" "2D Fix" "3D Fix" "DGPS Fix" "1PPS Active" "Radio 1 Power" "Radio 2 Power" "Radio 3 Power" "Radio 4 Power" "Radio 1 Sync" "Radio 2 Sync" "Radio 3 Sync" "Radio 4 Sync" "Radio 1 Tripped" "Radio 2 Tripped" "Radio 3 Tripped" "Radio 4 Tripped" "SyncPipe Power" "SyncPipe Tripped" "Switch to NMEA" "2D Fix" "3D Fix" "DGPS Fix" "1PPS Active"

DEBUG1: "Relay

SNMP COMMAND FROM CLI

$ snmpwalk -O qv -v2c -c<community> <ip> .1.3.6.1.4.1.32050.2.1.26.2
"Relay Output"
"Expansion Power"
"Expansion Tripped"
"Switch Input"
"Radio 1 Power"
"Radio 2 Power"
"Radio 3 Power"
"Radio 4 Power"
"Radio 1 Sync"
"Radio 2 Sync"
"Radio 3 Sync"
"Radio 4 Sync"
"Radio 1 Tripped"
"Radio 2 Tripped"

Answer 1

I'd be more confident about this if you'd given example input (I don't know what the output of snmpwalk looks like). But from what I understand, you're expecting the array to split the text only at newlines, not at spaces. By default, bash splits at spaces, tabs, and newlines. To change that behavior, you can modify the value of IFS ( nput ield eparator):

OLDIFS="$IFS"
IFS=$'\n'      # newlines are the only separator
IN=($(my_command ...))
IFS="$OLDIFS"

The extra two lines save and restore the value of IFS, in case other parts of your script depend on it.

(Incidentally, if you google "bash array newlines" you find some things explaining this.)

Answer 2

Try something like this:

mlm@matt-mmf-macbook.local:~
$ a=( "data1 data2" "data3 data4" )

mlm@matt-mmf-macbook.local:~
$ echo "${a[0]}"
data1 data2

mlm@matt-mmf-macbook.local:~
$ echo "${a[1]}"
data3 data4