grep and find on MacOS

6/21/20

My last post was about some useful bash commands like grep and find. I just learned that while Mac OS is a unix based system, these commands work a tad differently. For example, on Linux

$ grep "baseball" -r

needs to be changed to

$ grep "baseball" -r .

Otherwise you get a very spooky grep: warning: recursive search of stdin. The . at the end is needed to specify the location to search recursively. A similar thing happens with find.

For example, on Linux…

$ find -regex ".*_names"

turns into

$ find . -regex ".*_names"

Again, we need the . in order to specify the location of the search.

Expanding search results in grep

The grep usage I showed above only shows the line on which the match occurs. By using the -B and -A options we can specify how many lines before and after we want to see. For example:

$ grep -B 1 -A 1 "baseball" searchme.txt

Here is a sentence before.
baseball
This is the sentence after.

And now grep will show 1 sentence before (-B) and 1 sentence after (-A) the match.

Onward to more command line knowledge…