Fix set-fqdn to preserve localhost entries in /etc/hosts

[Copilot]

Fix /etc/hosts handling in node/set-fqdn action

Changes Made

• Understand the current sed command behavior
• Modify the script to:
  • Skip commenting lines with IP 127.0.0.1 or ::1 that contain "localhost", "localhost4", or "localhost6"
  • Remove the old hostname from those specific localhost lines instead (completely, without extra spaces)
  • Still comment out other lines containing the old hostname
• Test the changes manually with comprehensive test cases
• Address review feedback to completely remove hostname without replacement
• Run security scanning (shellcheck, bash syntax validation)

Technical Details

Modified core/imageroot/var/lib/nethserver/node/actions/set-fqdn/20set_fqdn:

• Changed sed pattern to use \s+ to match one or more spaces
• Added space normalization step s/\s+/ /g to collapse multiple spaces
• This completely removes the old hostname without leaving extra spaces

Example (from problem statement)

Before:

127.0.0.1   nethvoice localhost localhost.localdomain localhost4 localhost4.localdomain4

After (now correctly removes hostname without extra spaces):

127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4

Testing

All comprehensive tests pass:

• ✓ Hostname completely removed from localhost lines
• ✓ No double/extra spaces in the result
• ✓ Non-localhost entries properly commented
• ✓ Shellcheck passes
• ✓ Bash syntax validation passes

Original prompt

The node/set-fqdn action must not comment the /etc/hosts line that has IP 127.0.0.1 or ::1 and name "localhost" or "localhost4" or "localhost6". Instead it must clear it from the old host name if such line matches it.

 127.0.0.1   nethvoice localhost localhost.localdomain localhost4 localhost4.localdomain4

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[DavidePrincipi]

@copilot is this substitution adding a space " " to the matching line? The old hostname must be completely removed (without replacement).

[Copilot]

You're correct. The previous implementation was replacing with a space. Fixed in commit f987503 to completely remove the hostname using s/\s+${old_hostname}\s+/ /g and added s/\s+/ /g to normalize any multiple spaces into single spaces.

[DavidePrincipi]

Refs NethServer/dev#7856