When working with Linux performance monitoring, the top command is one of the first tools sysadmins and developers reach for. However, its package location varies across distributions. In CentOS/RHEL systems, you'll find it in the procps-ng package, not util-linux or coreutils as some might assume.

To identify which package provides top on your CentOS system:

rpm -qf $(which top)
# Sample output: procps-ng-3.3.10-26.el8.x86_64

For Debian-based systems, you'd use:

dpkg -S $(which top)
# Sample output: procps: /usr/bin/top

When creating deployment scripts or container images, explicitly declaring dependencies becomes crucial. If you're writing a script that requires top, your package installation command should be:

# For CentOS/RHEL:
yum install procps-ng

# For Debian/Ubuntu:
apt-get install procps

Many developers prefer alternative implementations like htop. Here's how to configure an alias in your .bashrc:

# Check if htop exists, fall back to top
if [ -x "$(command -v htop)" ]; then
    alias top='htop'
else
    echo "Consider installing htop for enhanced features:"
    echo "  yum install epel-release && yum install htop"
fi

When building Docker images, your Dockerfile should explicitly include the required package:

FROM centos:8
RUN yum install -y procps-ng \
    && yum clean all
CMD ["top"]

The package contains other essential utilities you might need:

• vmstat - Virtual memory statistics
• free - Memory usage information
• ps - Process status (though some distributions put this in procps)

If you encounter a "command not found" error, verify the package is installed:

# CentOS/RHEL 7/8:
yum list installed | grep procps

# CentOS Stream/RHEL 9:
dnf list installed | grep procps

To see all files provided by the package:

rpm -ql procps-ng

On CentOS and RHEL systems, the top command is actually distributed through the procps-ng package, not util-linux or coreutils as one might initially assume. This often causes confusion because:

• Basic system utilities are typically split between util-linux and coreutils
• System monitoring tools frequently have different package dependencies

To confirm which package provides top on your CentOS system:

# Method 1: Using rpm
rpm -qf $(which top)

# Method 2: Using yum/dnf
dnf provides */top
# or for older CentOS versions:
yum whatprovides */top

Example output should show:

procps-ng-3.3.10-26.el8.x86_64 : System and process monitoring utilities
Repo        : @System
Matched from:
Filename    : /usr/bin/top

If you need to install or reinstall the package:

# Install procps-ng
sudo dnf install procps-ng

# Verify installed version
rpm -q procps-ng --info

# Check all utilities provided by the package
rpm -ql procps-ng | grep bin/

While discussing top, it's worth mentioning other system monitoring utilities that often coexist in the same ecosystem:

• vmstat - Virtual memory statistics
• free - Memory usage information
• ps - Process status (though modern systems often have this in procps-ng)
• htop - Enhanced alternative (requires separate installation)

The procps-ng package is actually a new generation of the original procps package, with improvements including:

• Better multiprocessor support
• Improved memory reporting
• Enhanced command-line options
• Regular security updates

For developers working on system monitoring applications, understanding these package dependencies is crucial when:

• Building minimal container images
• Creating installation scripts
• Troubleshooting missing commands
• Developing system monitoring tools