It turned out that the command I regularly use to search a bunch of data is not known to others.

I frequently use fgrep to grep against a list of keywords (i.e. IDs).

fgrep -f keywords.txt data.txt

where keywords.txt contains a list of keywords ('one keyword in one line' manner), and data.txt is a bunch of data to be greped.

In fact, we can make use of grep -f command instead of fgrep -f. I am not sure about the difference currently.

Written by bonohu in shell on 木 18 4月 2019.