Using grep for multiple search patterns

Question

Consider I have the following stream of data:

BODY1
attrib1:  someval11
attrib2:  someval12
attrib3:  someval13

BODY2
attrib1:  someval21
attrib2:  someval22
attrib3:  someval23

BODY3
attrib1:  someval31
attrib2:  someval32
attrib3:  someval33

I want to extract only attrib1 and attrib3 for each BODY, i.e.

attrib1:  someval11
attrib3:  someval13
attrib1:  someval21
attrib3:  someval23
attrib1:  someval31
attrib3:  someval33

I tried

grep 'attrib1\|attrib3', according to this site but that returned nothing. grep attrib1 and grep attrib2 do return data but just for the single pattern specified.

Answer 1

grep -e 'attrib1' -e 'attrib3' file

From the man page :

-e PATTERN, --regexp=PATTERN
Use PATTERN as the pattern. This can be used to specify multiple search patterns, or to protect a pattern beginning with a hyphen (-). (-e is specified by POSIX.)

Edit : Alternatively , you can save patterns in a file and use the -f option :

aman@aman-VPCEB14EN:~$ cat>patt
attrib1
attrib3

aman@aman-VPCEB14EN:~$ grep -f patt test
attrib1:  someval11
attrib3:  someval13
attrib1:  someval21
attrib3:  someval23
attrib1:  someval31
attrib3:  someval33