Using 'grep' to find lines that contain all of three specified characters in any order

Question

We have a document which contains lines and we have to find if [a|b|c] appears at least once in every line no matter which order.

For example:

Input:

abc
bca
cab
hhfdhdhfabjfdjdjff
acjfdjdfjdf
fhfhfhfabcjdfjdjfk
ahfhfbkjfjdjffc

Desired Output (the fourth line is absent since it only contains a and b but no c):

abc
bca
cab
fhfhfhfabcjdfjdjfk
ahfhfbkjfjdjffc

We are using Linux.

Answer 1

Pipe it:

grep a file | grep b | grep c

Answer 2

The sed advantage of grep easy to see in such examples

sed -n '/a/{/b/{/c/p;};}' file

or:

sed '/a/!d;/b/!d;/c/!d' file

Answer 3

awk '/a/ && /b/ && /c/' file

Or with grep (which wouldn't scale well, though):

grep -e 'a.*b.*c' -e 'a.*c.*b' -e 'b.*a.*c' -e 'b.*c.*a' -e 'c.*a.*b' -e 'c.*b.*a'  file

Answer 4

Let's compare all proposed solutions!

I have a text file test.txt of size ~230M. I'm on Mac Mini, updated to 10.10.

1) awk solution by Hauke Laging (better not...):

$ time bash -c "awk '/a/ && /b/ && /c/' >> /dev/null"
19.51 real        19.23 user         0.20 sys

2) "bruteforced" grep by Raghuraman R and Hauke Laging (better, but not really...):

$ time bash -c "grep -e 'a.*b.*c' -e 'a.*c.*b' -e 'b.*a.*c' -e 'b.*c.*a' -e 'c.*a.*b' -e 'c.*b.*a' test.txt >> /dev/null"
10.02 real         9.93 user         0.07 sys

3) chained grep by muru (ok!):

$ time bash -c "grep a test.txt | grep b | grep c >> /dev/null"
1.61 real         3.08 user         0.29 sys

4) perl solution by terdon (even better!):

$ time bash -c "perl -ne 'print if /a/ && /b/ && /c/' test.txt >> /dev/null"
0.83 real         0.75 user         0.07 sys

So, I think "chained grep" is ok, but you can also use Perl for even better performance. I could not test sed approach, because the program provided by Costas does not work "as is" in mac os console.

BTW I'm no expert on benchmarking, sorry if I did something wrong.

Answer 5

Through grep which accept -P (Perl-regexp) parameter.

$ grep -P '^(?=.*a)(?=.*b)(?=.*c)' file
abc
bca
cab
fhfhfhfabcjdfjdjfk
ahfhfbkjfjdjffc

Explanation:

• ^ Matches the start of a line
• (?=.*a) Only if the string going to be matched must contain a letter a
• (?=.*b) Must contain b
• (?=.*c) Must contain c

Answer 6

I would do this in perl instead:

$ perl -ne 'print if /a/ && /b/ && /c/' file 
abc
bca
cab
fhfhfhfabcjdfjdjfk
ahfhfbkjfjdjffc

If you just want to check whether each line matches all three letters (without printing the line itself), you could do:

$ perl -lne '$k++ if /a/ && /b/ && /c/; 
 END{$k==$. ? print "yes" : print "no"}' file

Or

$ awk '(/a/ && /b/ && /c/){k++} END{if(k==NR){print "yes"} else{print "no"}}' file

Answer 7

If it is just a,b,c then we can use a mix of 'grep -o' and 'grep -e' option as below

grep -e "a.*b.*c" -e "a.*c.*b" -e "b.*a.*c" -e "b.*c.*a" -e "c.*a.*b" -e "c.*b.*a" file

You can also check already asked question at https://stackoverflow.com/questions/1546711/can-grep-show-only-words-that-match-search-pattern

Answer 8

if [ $(grep a file | grep b | grep -c c) -eq $(wc -l file | cut -f1 -d' ') ]; then
    echo yes
else
    echo no
fi