Filtered Windows comand works on it's own inside WSL, but not in a script-CodePudding

I have this command which returns an IP successfully:

user@laptop:~$ systeminfo.exe | sed -n '/Connection Name: vEthernet (WSL)/, 4p' | egrep --word-regexp '\[01\]:' | awk '{print $2}'
172.22.0.1

I am trying to concatenate and export an environmental variable DISPLAY using a script with this content:

LOCAL_IP=$(systeminfo.exe | sed -n '/Connection Name: vEthernet (WSL)/, 4p' | egrep --word-regexp '\[01\]:' | awk '{print $2}')
export DISPLAY=$LOCAL_IP:0

But after this script runs, DISPLAY doesn't look like expected:

user@laptop:~$ echo $DISPLAY
:02.22.0.1

I was expecting an answer 172.22.0.1:0. What went wrong?

CodePudding user response：

LOCAL_IP appears to have a trailing \r; od -c <<< "${LOCAL_IP}" should show the value ending in a \r

One fix using parameter substitution:

$ export DISPLAY="${LOCAL_IP//$'\r'/}:0"
$ echo "${DISPLAY}"
172.22.0.1:0

Another option would be to add an additional pipe on the end of OP's current command, a couple ideas (dos2unix, tr -d '\r'); 3rd option modifies the awk script to remove the \r:

systeminfo.exe | sed -n '/Connection Name: vEthernet (WSL)/, 4p' | egrep --word-regexp '\[01\]:' | awk '{print $2}' | dos2unix

# or

systeminfo.exe | sed -n '/Connection Name: vEthernet (WSL)/, 4p' | egrep --word-regexp '\[01\]:' | awk '{print $2}' | tr -d '\r'

# or

systeminfo.exe | sed -n '/Connection Name: vEthernet (WSL)/, 4p' | egrep --word-regexp '\[01\]:' | awk '{gsub(/\r/,"");print $2}'

Another option would be to replace the sed/egrep/awk/tr with a single awk call. If OP wants to go this route I'd recommend asking a new question, making sure to provide the complete output from systeminfo.exe to better understand the parsing requirements.