Searching strings on files

Question

I've got a bunch on strings which I need to find in a couple of files, for example:

string1
string2
stringn

file1.txt
file2.txt
filen.txt

Is there an (easy) way to do that in bash? I need to know, if a string was found, in which file is it.

Answer 1

Simple grep command with -e option:

 grep -e "string1" -e "string2" -e "stringn" file*.txt

Or you can put all the search strings in a file called search.txt like this:

string1
string2
string3
...
...
stringN

and then run grep like this with -f option:

grep -f search.txt file*.txt

Answer 2

Use grep to search for all the strings in one pass:

grep -E -H 'string1|string2|stringn' file1.txt file2.txt filen.txt

The -E lets you use the pipe character(|) without escaping it. The -H prints the filename for each match. The regular expression uses pipes to separate each string, so that grep will try to match each one in order.

Answer 3

There is a variant of grep that supports this feature for large sets of strings, try

fileWithListOfSearchTargets=myFileOfSearchTargets.txt

fgrep -f ${fileWithListOfSearchTargets} file1 file2 ... filen

(The variable and filenames are meant to be self-documenting, you can use any name you like)

You have to enter all your search strings into the file.

No leading or trailing spaces unless you expect those to match in your filelist. There is a limit to the size that most fgreps can process. Don't try to cram 10K lines into one file.

Answer 4

The best way is to use grep:

grep -H 'string to search' file1.txt file2.txt filen.txt

will search the specified files for a string, and print out the matching lines along with the filename where the match was found.

Answer 5

Unix find command:

find . -exec grep "i want to find this string" '{}' \; -print

will search from current dir and down.

This works too:

egrep -r 'arbitrary string' *

Answer 6

egrep "(string1|string2|string3)" file{1..3}.txt