egrep:tldr:13e22

The command egrep "${search_pattern}" ${filename} is used to search for a specified pattern within a text file. Here is an explanation of this command:

• egrep is a command-line tool that is used to search for regular expressions in text. It is similar to the grep command but supports extended regular expressions.
• "${search_pattern}" is a variable that holds the pattern you want to search for. The double-quotes around the variable ensure that the pattern is treated as a single argument, even if it contains spaces or special characters.
• ${filename} is a variable that specifies the name of the file you want to search in. This can be the absolute or relative path to the file.

When you run this command, egrep will search for the specified pattern (${search_pattern}) in the file specified by ${filename}. It will then display all the lines in the file that match the pattern.