Replace string in text file with PowerShell

Question

I am attempting to replace a string in a text file on a specific line number using PowerShell but the command is removing a majority of the content. I would like to leverage the line number because the string to be replaced occurs on several lines but only want the string on line 51 to be updated. I am currently attempting to use the following to perform the replacement:

$content = Get-Content "file.txt"
$contentUpdate = $content[51] -replace '"Endpoint": ""','"Endpoint": "bucket.s3.us-west-1.vpce.amazonaws.com",'
Set-Content file.txt $contentUpdate

When the above commands are run against the file referenced at the bottom of this question, only the following remains in the file:

 "Region": "",

File content:

{
 "Profile":{
 "ShareCreds" : true,
 "ShareProfile" : "",
 "ForceUpdateCreds" : false,
 "KeyAutoRotateDays": 0
 },
 "Mds": {
 "CommandWorkersLimit" : 5,
 "StopTimeoutMillis" : 20000,
 "Endpoint": "",
 "CommandRetryLimit": 15
 },
 "Ssm": {
 "Endpoint": "",
 "HealthFrequencyMinutes": 5,
 "CustomInventoryDefaultLocation" : "",
 "AssociationLogsRetentionDurationHours" : 24,
 "RunCommandLogsRetentionDurationHours" : 336,
 "SessionLogsRetentionDurationHours" : 336,
 "PluginLocalOutputCleanup": "",
 "OrchestrationDirectoryCleanup": ""
 },
 "Mgs": {
 "Region": "us-west-1",
 "Endpoint": "",
 "StopTimeoutMillis" : 20000,
 "SessionWorkersLimit" : 1000,
 "DeniedPortForwardingRemoteIPs" : [
 "169.254.169.254",
 "fd00:ec2::254",
 "169.254.169.253",
 "fd00:ec2::253"
 ]
 },
 "Agent": {
 "Region": "",
 "OrchestrationRootDir": "",
 "SelfUpdate": false,
 "TelemetryMetricsToCloudWatch": false,
 "TelemetryMetricsToSSM": true,
 "AuditExpirationDay" : 7,
 "LongRunningWorkerMonitorIntervalSeconds": 60
 },
 "Os": {
 "Lang": "en-US",
 "Name": "",
 "Version": "1"
 },
 "S3": {
 "Endpoint": "",
 "Region": "",
 "LogBucket":"",
 "LogKey":""
 },
 "Kms": {
 "Endpoint": ""
 }
}

• Mathias R. Jessen: Change $contentUpdate = $content[51] -replace ... to $content[51] = $content[51] -replace ..., then replace the last line with Set-Content file.txt $content (although it looks like 51 is not the correct line index)

Answer 1

Well, seeing that this is a JSON you're working with, I would treat it as such:

$content = Get-Content "file.txt" -Raw | ConvertFrom-Json
$content.S3.Endpoint = "bucket.s3.us-west-1.vpce.amazonaws.com"
$content | ConvertTo-Json | Set-Content "file.txt"

This way you avoid trying to index through an array and work with the objects themselves.