The grep command is a Linux shell one for finding strings.
The following is by my understanding.
The grep command is used to find a string and will print out each line that contains it.
grep “log” a-file.txt
will print, to terminal, each line from a-file.txt that contains the string “log”.
grep log a-file.txt
seems to work the same as if “log” is in quotes.
The grep command can be used with regular expressions. For example,
grep -E gre”e|a”t a-file.txt
will find “great” or “greet” in a-file.txt. The -E switch means you don’t need to escape the | operator.
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