The grep command

• grep <pattern> <files> Scans the given files and displays the lines which match the given pattern.

• grep error *.log Displays all the lines containing error in the *.log files

• grep -i error *.log Same, but case insensitive

• grep -ri error . Same, but recursively in all the files in . and its subdirectories

• grep -v info *.log Outputs all the lines in the files except those containing info.