How do I check pending Linux updates without installing them?
Refresh the configured repository metadata, then list available updates without starting an upgrade. This separates information gathering from a change to installed software. Review distribution security advisories when deciding urgency; a package name or version number alone does not tell you whether your workload is affected.
Before you start
- An authorised SSH session on the Linux server.
Instructions
1. Review Debian or Ubuntu updates
Refreshing the package index writes local cache metadata but does not upgrade installed packages. Repository access and valid signing configuration must already be in place.
sudo apt-get update
apt list --upgradableResolve repository errors before treating the available-update list as complete. This second command is for interactive review.
2. Use the RPM-family alternative
On a server using DNF, check the available updates through its configured repositories. The command may refresh metadata as part of the check.
dnf check-updateDNF returns status 100 when updates are available, 0 when none are available, and a different failure status for an error. Do not interpret 100 as a failed upgrade.
Check the result
- The repository refresh succeeds and the listed candidates are understood. Installing updates remains a separate maintenance action with application checks.
Troubleshooting
- No updates appear despite a security notice
- Check the distribution release, enabled repositories, subscription status, package pinning and whether the advisory applies to your installed build.
- Metadata retrieval fails
- Fix time, DNS, proxy, trust or repository availability rather than bypassing signature verification.
Official references
Use the documentation for your installed version when a flag, service name or platform feature differs.