var/log/messages:Dec 28 10:36:52 centos7vm kernel: ACPI: PCI Interrupt Link (IRQs 5 *9 10 11) var/log/messages:Dec 28 10:36:52 centos7vm kernel: ACPI: PCI Interrupt Link (IRQs 5 9 *10 11) var/log/messages:Dec 28 10:36:52 centos7vm kernel: ACPI: PCI Interrupt Link (IRQs 5 9 10 *11)

var/log/messages:Dec 28 10:36:52 centos7vm kernel: ACPI: Using IOAPIC for interrupt routing Output: $ sudo grep err /var/log/messages* Here’s how you can look for a pattern in multiple files by using * wildcard. Grep enables you to search for the given pattern not just in one but multiple files. Grep command expects a pattern and optional arguments along with a file list if used without piping. So let’s get started…👨‍💻 grep Command Syntax Here we will be covering some of the commonly used grep command in different scenarios by sysadmin or developer. The power of regular expression combines with supported options in grep makes this possible. It’s often used to filter out unnecessary details while printing just the required information from big log files. grep basically searches for a given pattern or regular expression from standard input or file and prints the lines that match the given criteria. Its name comes from another similar command in ed tool, i.e., g/re/p which stands for globally search for a regular expression and print matching lines. Grep, originally developed for Unix-based systems, is one of the most widely used command-line utility in Linux boxes.

Grep means