CODEWITHSUNDEEP
bashgrep
Olha Kholod
Olha Kholod

Reputation: 559

select multiple patterns with grep

I have file that looks like that:

t # 3-7, 1
v 0 104
v 1 92
v 2 95
u 0 1 2
u 0 2 2
u 1 2 2
t # 3-8, 1
v 0 94
v 1 13
v 2 19
v 3 5
u 0 1 2
u 0 2 2
u 0 3 2
t # 3-9, 1
v 0 94
v 1 13
v 2 19
v 3 7
u 0 1 2
u 0 2 2
u 0 3 2

t corresponds to header of each block.

I would like to extract multiple patterns from the file and output transactions that contain required patterns altogether.

I tried the following code:

ps | grep -e 't\|u 0 1 2' file.txt

and it works well to extract header and pattern 'u 0 1 2'. However, when I add one more pattern, the output list only headers start with t #. My modified code looks like that:

ps | grep -e 't\|u 0 1 2 && u 0 2 2' file.txt

I tried sed and awk solutions, but they do not work for me as well.

Thank you for your help! Olha

Upvotes: 0

Views: 402

Answers (3)

l0b0
l0b0

Reputation: 58808

Expanding on @kojiro's answer, you'll want to use an array to collect arguments:

mapfile -t lines < file.txt
for line in "${lines[@]}"
do
    arguments+=(-e "$line")
done

grep "${arguments[@]}"

You'll probably need a condition within the loop to check whether the line is one you want to search for, but that's it.

Upvotes: 0

Barmar
Barmar

Reputation: 780984

Use | as the separator before the third alternative, just like the second alternative.

grep -E 't|u 0 1 2|u 0 2 2' file.txt

Also, it doesn't make sense to specify a filename and also pipe ps to grep. If you provide filename arguments, it doesn't read from the pipe (unless you use - as a filename).

Upvotes: 1

kojiro
kojiro

Reputation: 77107

You can use grep with multiple -e expressions to grep for more than one thing at a time:

$ printf '%d\n' {0..10} | grep -e '0' -e '5'
0
5
10

Upvotes: 1

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