Fetch line starting with a specific string in powershell - regex

Question

I am executing a command for which I am getting output like below
Identifier: 3 SFP
Connector: 7 LC
Transceiver: 7004404000000000 4,8,16_Gbps M5 sw Short_dist
Encoding: 6 64B66B
Baud Rate: 140 (units 100 megabaud)
Length 9u: 0 (units km)
Length 9u: 0 (units 100 meters)
Length 50u (OM2): 3 (units 10 meters)
Length 50u (OM3): 10 (units 10 meters)
Length 62.5u:0 (units 10 meters)
Length Cu: 0 (units 1 meter)
Vendor OUI: 00:05:1e
Vendor PN: 57-0000088-01
Vendor Rev: A
Wavelength: 850 (units nm)
Options: 003a Loss_of_Sig,Tx_Fault,Tx_Disable
BR Max: 0
BR Min: 0
Date Code: 180316
DD Type: 0x68
Enh Options: 0xfa
Status/Ctrl: 0xb2
Pwr On Time: 3.52 years (30822 hours)
E-Wrap Control: 0
O-Wrap Control: 0
Alarm flags[0,1] = 0x5, 0x40
Warn Flags[0,1] = 0x5, 0x40
Temperature: 32 Centigrade
Current: 8.082 mAmps
Voltage: 3311.6 mVolts
RX Power: -5.5 dBm (280.4uW)
TX Power: -2.8 dBm (523.1 uW)
I need to fetch the last 2 lines only, that is starting with RX and TX out of it.
I was trying like
#$streamOut | Select-String -Pattern "^RX" | select -ExpandProperty line
$streamOut | Select-String -Pattern "RX" | select -ExpandProperty line
This is by code
$session = New-SSHSession -ComputerName $SAN_IP -Credential $cred
$Strem = New-SSHShellStream -SSHSession $Session
$streamOut=#()
$SystemView = $Strem.WriteLine("sfpshow $port_Num")
sleep -Seconds 5
$streamOut = #($Strem.read())
sleep -Seconds 5
$RXTX_Data = #($streamOut | ? { $_ -match "^RX" -or $_ -match "^TX"})
$RXTX_Data
When I use the below solution in above code, it is returning blank. the $streamOut is array
PS C:\Windows\system32> $streamOut.GetType()
IsPublic IsSerial Name BaseType
-------- -------- ---- --------
True True Object[] System.Array
But it is returning the entire output.
Please let me know on this

Answer 1

As you clarified, the $streamOut variable contains a single, multiline string.
In this case you can use Select-String with -AllMatches like this:
$RXTX_Data = ($streamOut | Select-String -Pattern '(?m)^(RX|TX).*$' -AllMatches).Matches.Value
$RXTX_Data # Output array of matching lines
Output:
RX Power: -5.5 dBm (280.4uW)
TX Power: -2.8 dBm (523.1 uW)
Note that it is important to use the (?m) inline modifier for multiline mode, which changes behaviour of ^ to anchor beginning of line and $ to anchor end of line, instead of beginning and end of whole input string.
An easier alternative is to split the string into lines first, so you can use the -match operator to filter for matching lines:
$streamLines = $streamOut -split '\r?\n'
$RXTX_Data = $streamLines -match '^(RX|TX)'
This works because -match and other comparison operators act as a filter when the LHS operand is a collection like an array. We don't need multiline mode, because the RegEx gets applied to each array element (line) individually.
The above two lines could even be condensed into a one-liner:
$RXTX_Data = ($streamOut -split '\r?\n') -match '^(RX|TX)'

Answer 2

try this :
$streamOut = Get-Content -Path "Your_Output_FilePath"
$streamOut | ? { $_ -match "^RX" -or $_ -match "^TX"}