How can I grep a file using OR

Question

I want to search a file with either this string 'foo' or this string 'bar'. This is what I've attempted so far:

cat filename.csv | grep foo\|bar

Answer 1

You can specify multiple patterns with multiple -e flags:

grep -e foo -e bar filename.csv

This is a POSIX standard.

Answer 2

What I suggested earlier does not work on some installations. I believe this is a more portable syntax:

grep -E 'foo|bar' filename.csv

The above is an alternative form of:

egrep 'foo|bar' filename.csv

egrep supports use of a regular expression, which in this case is 'foo|bar'

Answer 3

将egrep与正则表达式一起使用。

cat filename.csv | egrep 'foo|bar'

Answer 4

You can use any of following.

cat filename.csv | grep -E 'foo|bar'

grep -E 'foo|bar' filename.csv