How to find a string in files in linux Ubuntu

The  commands used are mainly grep and find.

Find string in file

grep string filename

grep name file.txt

Find string in file ignoring cases

grep string filename

grep -i name file.txt

Find string in current directory

grep string .

grep name .

Find string recursively

grep -r string .

grep -r name .

Find files that do not contain a string

grep -L string .

grep -L "foo" *

Find string recursively in only some specific files

grep  string -r . --include=*.myextension 

grep  string -r . --include=*.{myextension,myextension2}

grep "name=Oscar" -r . --include=*.js

* if you specify --include it won't look for the string in all files, just the ones included

Find string recursively in all files except the ones that contain certain extensions

grep  string -r . --exclude=*.{myextension2}

grep "Serializable" -rl . --exclude=*.{jar,class,svn-base,index}

Find string recursively all files including some extensions and excluding others

grep  string -r . --include=*.myextension  --exclude=*.myextension2

grep  string -r . --include=*.{myextension,myextension2} --exclude=*.{myextension3,myextension2}

grep "my=string" -r . --include=*.{js,html} --exclude=*.js

*It won't look for the string in the js files.

Find string recursively in only some specific files and show their filename

grep  string -rl . --include=*.myextension

grep "name=Oscar" -rl . --include=*.js

Find files and find a string in them using find

find . -name '*.extension' -exec grep string +

find . -name '*.txt' -exec grep Mytext {} +

find . -type f \( -name '*.htm' -or -name '*.html' \) -exec grep -i "mystring" {} +

Notes

• Use double quotes "String" if the string contains spaces
• Mind the empty spaces between extensions between the curly braces e.g.{txt, html}
• Don't use curly braces for one extension e.g{html}