ping mirrors.tencentyun.com -c 3

cat /etc/resolv.conf
# Ensure that the nameserver configuration is correct

# Check the local firewall
firewall-cmd --list-all

# Check HTTP access
curl -I http://mirrors.tencentyun.com/tlinux/

dnf repolist
dnf makecache

Error: Failed to synchronize cache for repo '...'

ls /etc/yum.repos.d/

# Back up existing repo files
mkdir -p /etc/yum.repos.d/backup
mv /etc/yum.repos.d/*.repo /etc/yum.repos.d/backup/

# View the system version
cat /etc/os-release

# Reconfigure the standard repository (TencentOS Server 4, consistent with the system default configuration)
cat > /etc/yum.repos.d/TencentOS.repo << 'EOF'
[BaseOS]
name=TencentOS Server $releasever - BaseOS
baseurl=http://mirrors.tencentyun.com/tlinux/$releasever/BaseOS/$basearch/os/
        http://mirrors.tencent.com/tlinux/$releasever/BaseOS/$basearch/os/
gpgcheck=1
enabled=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-TencentOS-4

[AppStream]
name=TencentOS Server $releasever - AppStream
baseurl=http://mirrors.tencentyun.com/tlinux/$releasever/AppStream/$basearch/os/
        http://mirrors.tencent.com/tlinux/$releasever/AppStream/$basearch/os/
gpgcheck=1
enabled=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-TencentOS-4

[extras]
name=TencentOS Server $releasever - extras
baseurl=http://mirrors.tencentyun.com/tlinux/$releasever/extras/$basearch/os/
        http://mirrors.tencent.com/tlinux/$releasever/extras/$basearch/os/
gpgcheck=1
enabled=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-TencentOS-4
EOF

dnf clean all
dnf makecache

No match for argument: <package-name>
Error: Unable to find a match

cat /etc/os-release

# Search for software packages (fuzzy match)
dnf search <keyword>

# Find which package provides a command or file
dnf provides /usr/bin/curl
dnf provides "*/libssl.so*"

# TencentOS Server 4: Enable EPOL (the TencentOS adaptation of EPEL, installed by default in standard images)
dnf install -y epol-release
# Confirm that the EPOL source configuration file exists
ls /etc/yum.repos.d/epol.repo

# For third-party software (such as Docker), you can add the official repo
dnf config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo

SyntaxError: invalid syntax

# Check the shebang line of /usr/bin/dnf
head -1 /usr/bin/dnf
# It should be #!/usr/bin/python3

# If it is incorrect, fix it
sed -i '1s|.*|#!/usr/bin/python3|' /usr/bin/dnf

head -1 /usr/bin/dnf
# It should be #!/usr/bin/python3

# Use pyenv to manage Python versions (without affecting the system Python)
curl https://pyenv.run | bash
pyenv install 3.11.0
pyenv global 3.11.0

Error: Problem: package X requires Y, but none of the providers can be installed

# View dependencies
dnf deplist <package-name>

# View the cause of the conflict
dnf install --best <package-name>

# Skip broken dependencies (not recommended, as it may cause system instability)
dnf install --skip-broken <package-name>

# Try to directly download and install the RPM (ignoring repo dependencies)
dnf download <package-name>
rpm -ivh --nodeps <package>.rpm

GPG key retrieval failed

# Temporarily skip GPG verification (for debugging)
dnf install --nogpgcheck <package-name>

# Import the official Tencent GPG key (built into the system)
rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-TencentOS-4

# Permanently skip GPG in the repo file (not recommended, as it reduces security)
# gpgcheck=0

OSError: [Errno 28] No space left on device

# View disk usage
df -h

# Clear the dnf cache
dnf clean all
# Cache location: /var/cache/dnf/

# Clean up old kernels (keep the current and previous versions)
dnf remove $(dnf repoquery --installonly --latest-limit=-2 -q)

# View large files
du -sh /var/cache/dnf/

# Install a software package
dnf install -y <package-name>

# Update all software packages
dnf update -y

# Update a single software package
dnf update -y <package-name>

# Remove a software package
dnf remove <package-name>

# Search for software packages
dnf search <keyword>

# View software package information
dnf info <package-name>

# List installed software packages
dnf list installed

# View software package update history
dnf history

# Roll back to the last dnf operation
dnf history undo last

# Clear caches
dnf clean all

# Download only without installing
dnf download <package-name>
dnf download --resolve --alldeps <package-name>  # Includes all dependencies