You work as a Network Administrator for Perfect Solutions Inc. The company has a Linux-based network. You are required to search for the error messages in the /var/log/messages log file. Which of…

The ps command displays currently running processes and cannot read or search file contents.

The look command performs prefix-based searching in sorted word files and is not designed for filtering arbitrary log file content.

The command cat /var/log/messages | grep error sends the full file contents through a pipe to grep, which filters and returns only the lines containing the string 'error'. This is the standard Linux pattern for searching plain-text log files for specific keywords, and grep supports regex patterns for more advanced filtering.

cat /var/log/messages alone outputs the entire file with no filtering, so error messages would not be isolated from the rest of the output.