Objective
The following article provides some useful tips on how to find all files within any specific directory or entire file-system containing any specific word or string.
Difficulty
EASY
Conventions
- # – requires given linux commands to be executed with root privileges either directly as a root user or by use of
sudocommand - $ – requires given linux commands to be executed as a regular non-privileged user
Examples
Find all files with a specific string non-recursively
The first command example will search for a string stretch in all files within /etc/ directory while excluding any sub-directories:
# grep -s stretch /etc/* /etc/os-release:PRETTY_NAME="Debian GNU/Linux 9 (stretch)" /etc/os-release:VERSION="9 (stretch)"
The -s grep option will suppress error messages about nonexistent or unreadable files. The output shows filenames as well as prints the actual line containing requested string.
Find all files with a specific string recursively
The above command omitted all sub-directories. To search recursively means to also traverse all sub-directories. The following linux command will search for a string stretch in all files within /etc/ directory including all sub-directories:
# grep -R stretch /etc/* /etc/apt/sources.list:# deb cdrom:[Debian GNU/Linux testing _Stretch_ - Official Snapshot amd64 NETINST Binary-1 20170109-05:56]/ stretch main /etc/apt/sources.list:#deb cdrom:[Debian GNU/Linux testing _Stretch_ - Official Snapshot amd64 NETINST Binary-1 20170109-05:56]/ stretch main /etc/apt/sources.list:deb http://ftp.au.debian.org/debian/ stretch main /etc/apt/sources.list:deb-src http://ftp.au.debian.org/debian/ stretch main /etc/apt/sources.list:deb http://security.debian.org/debian-security stretch/updates main /etc/apt/sources.list:deb-src http://security.debian.org/debian-security stretch/updates main /etc/dictionaries-common/words:backstretch /etc/dictionaries-common/words:backstretch's /etc/dictionaries-common/words:backstretches /etc/dictionaries-common/words:homestretch /etc/dictionaries-common/words:homestretch's /etc/dictionaries-common/words:homestretches /etc/dictionaries-common/words:outstretch /etc/dictionaries-common/words:outstretched /etc/dictionaries-common/words:outstretches /etc/dictionaries-common/words:outstretching /etc/dictionaries-common/words:stretch /etc/dictionaries-common/words:stretch's /etc/dictionaries-common/words:stretched /etc/dictionaries-common/words:stretcher /etc/dictionaries-common/words:stretcher's /etc/dictionaries-common/words:stretchers /etc/dictionaries-common/words:stretches /etc/dictionaries-common/words:stretchier /etc/dictionaries-common/words:stretchiest /etc/dictionaries-common/words:stretching /etc/dictionaries-common/words:stretchy /etc/grub.d/00_header:background_image -m stretch `make_system_path_relative_to_its_root "$GRUB_BACKGROUND"` /etc/os-release:PRETTY_NAME="Debian GNU/Linux 9 (stretch)" /etc/os-release:VERSION="9 (stretch)"
Search for all files containing a specific word
The above grep command example lists all files containing string stretch. Meaning the lines with stretches, stretched etc. are also shown. Use grep’s -w option to show only a specific word:
# grep -Rw stretch /etc/* /etc/apt/sources.list:# deb cdrom:[Debian GNU/Linux testing _Stretch_ - Official Snapshot amd64 NETINST Binary-1 20170109-05:56]/ stretch main /etc/apt/sources.list:#deb cdrom:[Debian GNU/Linux testing _Stretch_ - Official Snapshot amd64 NETINST Binary-1 20170109-05:56]/ stretch main /etc/apt/sources.list:deb http://ftp.au.debian.org/debian/ stretch main /etc/apt/sources.list:deb-src http://ftp.au.debian.org/debian/ stretch main /etc/apt/sources.list:deb http://security.debian.org/debian-security stretch/updates main /etc/apt/sources.list:deb-src http://security.debian.org/debian-security stretch/updates main /etc/dictionaries-common/words:stretch /etc/dictionaries-common/words:stretch's /etc/grub.d/00_header:background_image -m stretch `make_system_path_relative_to_its_root "$GRUB_BACKGROUND"` /etc/os-release:PRETTY_NAME="Debian GNU/Linux 9 (stretch)" /etc/os-release:VERSION="9 (stretch)"
List only files names containing a specific text
The above commands may produce an unnecessary output. The next example will only show all file names containing string stretch within /etc/ directory recursively:
# grep -Rl stretch /etc/* /etc/apt/sources.list /etc/dictionaries-common/words /etc/grub.d/00_header /etc/os-release
Perform case-insensitive search
All searches are by default case sensitive which means that any search for a string stretch will only show files containing the exact uppercase and lowercase match. By using grep’s -i option the command will also list any lines containing Stretch, STRETCH, StReTcH etc., hence, to perform case-insensitive search.
# grep -Ril stretch /etc/* /etc/apt/sources.list /etc/dictionaries-common/default.hash /etc/dictionaries-common/words /etc/grub.d/00_header /etc/os-release
Include or Exclude specific files names from search
Using grep command it is also possible to include only specific files as part of the search. For example we only would like to search for a specific text/string within configuration files with extension .conf. The next example will find all files with extension .conf within /etc directory containing string bash:
# grep -Ril bash /etc/*.conf OR # grep -Ril --include=\*.conf bash /etc/* /etc/adduser.conf
Similarly, using --exclude option we can exclude any specific filenames:
# grep -Ril --exclude=\*.conf bash /etc/* /etc/alternatives/view /etc/alternatives/vim /etc/alternatives/vi /etc/alternatives/vimdiff /etc/alternatives/rvim /etc/alternatives/ex /etc/alternatives/rview /etc/bash.bashrc /etc/bash_completion.d/grub /etc/cron.daily/apt-compat /etc/cron.daily/exim4-base /etc/dictionaries-common/default.hash /etc/dictionaries-common/words /etc/inputrc /etc/passwd /etc/passwd- /etc/profile /etc/shells /etc/skel/.profile /etc/skel/.bashrc /etc/skel/.bash_logout
Exclude specific Directories from search
Same as with files grep can also exclude specific directories from the search. Use --exclude-dir option to exclude directory from search. The following search example will find all files containing string stretch within /etc directory and exclude /etc/grub.d from search:
# grep --exclude-dir=/etc/grub.d -Rwl stretch /etc/* /etc/apt/sources.list /etc/dictionaries-common/words /etc/os-release
Display a line number containing searched string
By using -n option grep will also provide an information regarding a line number where the specific string was found:
# grep -Rni bash /etc/*.conf /etc/adduser.conf:6:DSHELL=/bin/bash
Find all files not containing a specific string
The last example will use -v option to list all files NOT containing a specific keyword. For example the following search will list all files within /etc/ directory which do not contain string stretch:
# grep -Rlv stretch /etc/*
