Find file that contains text linux

How to find all files containing specific text on Linux

How to search a directory tree for all files containing specific text string on Linux using the command line. This tutorial will help you to search all files matching a string recursively. This tutorial uses “grep” command to search string in files. Alternatively, You can also also use the find command to search files with specific string.

Syntax

grep -rwl “search-string” /path/to/serch/dir

1. Search Single String in All Files

Below example command will search string “tecadmin” in all files in /var/log directory and its sub-directories.

2. Search Multiple String in All Files

You can also specify multiple strings to search using -e switch. This is similar to egrep command. Below example will search strings “tecadmin” and “https” in all files in /var/log directory and its sub-directories.

3. Search String in Specific Files

You can search string in files matching the file name criteria. Below example command will search string “tecadmin” in files ending with .log extension in /var/log directory and its sub-directories.

4. Exclude Some Files from Search

If you want to exclude some files matching file name criteria. You can exclude some files using –exclude option in command. For example, do not search file ending with .txt extension.

5. Exclude Some Directories from Search

You can also exclude some directoires to skip search inside it. For example, do not search string files inside any folder having http in their name.

Frequently Uses Command Switches

Below is the frequently uses grep command switches. To list all switches details use grep —help command.

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Linux: Find Files Containing Text

This topic is essential knowledge for every user of UNIX, Linux, Solaris, OS X, and BSD. Furthermore, the LPI certification contains tricky questions about this.

If you want to find files with a certain filename using the command line then use either the find or the locate commands. But if you want to find files that contain a certain text you’ll want to use grep and its friends. Here, the term friends means a group of similar tools that are tailored to a specific data format, or file structure like plain text, compressed files, and PDF documents.

Basic Text Searching

The name grep is a combination of the initial letters of the four words «global / regular expression / print». This is similar to formulating search patterns in the stream editor sed . grep is designed to find according patterns in entire data streams (files). Given patterns are interpreted as text or Regular Expressions (see below for an example).

Example 1 displays how to discover all the occurrences of the brand name «Mikrotik» written either as «Mikrotik», or «MikroTik». We use grep to search through all files whose name starts with «invoice-2017». The result is a list of file names with the according matches — one per line preceded by the file name.

Example 1: Calling grep with an Regular Expression

This output is helpful but does not contain the line number. To show the line number with grep, use the option -n , or —line-number as the long version. Then, the result is as follows:

Example 2: Calling grep with an Regular Expression, and line numbers

On every line, the individual output fields are separated by colons. The first field contains the filename («invoice-20170015.text»), the second field is the line number within the matched file («64»), and the third field is the entire line with the matched text («Mikrotik Routerboard 750GL Gigabit Switch»).

More grep Options

grep has a long list of helpful options. See the manual page for a detailed description. The most relevant ones for this article are:

Short option	Long option	Description
-i	—ignore-case	lower and upper case writing
-l	—files-with-matches	stop after the first match, and output the file name
-n	—line-number	show the line number of the match
-r	—recursive	search recursively
—color or —colour	highlight the actual match

With the exception of highlighting the actual match, Example 3 combines the options -i , -r , and -l as described above. This simplifies the call, and returns a list of files with matches, no matter how many matches exist for each file. With the help of this you can see if there are matches at all, and if so, in which files.

Example 3: how to search for all files that contain the term «mikrotik» in any kind of spelling recursively

The command grep comes with two special variants — fgrep and egrep . fgrep interprets the search pattern as a string of single characters and is exactly the same as grep -F (and grep —fixed-strings ).

In contrast, egrep takes the pattern as a Regular Expression and is similar to grep -E (and grep —extended-regexp ). In older Linux releases prior Debian 4 Etch, both commands are implemented as shell scripts that call grep with special options. Nowadays, current Linux releases keep the commands as binary files. In either case the search is a bit quicker than using grep without this special option.

Searching Compressed Files

grep is unable to inspect compressed files properly. Now, the specialists named zgrep , bzgrep , xzgrep and zipgrep enter the stage. These tools help you to simplify commands like this:

zcat uncompresses the given file, and outputs its content to stdout . Piped to fgrep , the data stream is searched for the given [pattern] .

With the help of the commands above, you don’t have to unpack files compressed with gzip , bzip2 , xz and zip before searching — this step happens behind the scenes. As with grep , the special variants zfgrep and zegrep for gzip exist as well as bzfgrep and bzegrep for bz , and xzfgrep and xzegrep for xz archives. Example 4 shows how to search an xz -compressed file.

Example 4: Searching an xz -compressed file

Searching compressed archives is a bit more complex, and requires a bit of shell scripting. Listing 1 demonstrates such a shell script that works only with gzip -compressed archives. For simplicity, we saved the below script with the name «search.sh». The script requires two parameters — the search pattern, and the filename of the compressed archive (see Example 5 below).

Listing 1: Searching compressed gzip archives

Example 5: Calling the script

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Understanding the script may need a moment of time. First, the script extracts the list of files from the archive, and evaluates each file one after the next. The outer for loop does all the complex work. Second, the single matches are saved in the variable $match . Therefore, the current file is extracted from the compressed archive, and is then piped to fgrep . fgrep searches the data stream, and indicates a match with a positive return value. In case of that the following echo command is executed, and the file name is sent to stdout . Third, the actual match is printed as well, and followed by an empty line. This separates the different matches file-wise.

An alternative is the tool deepgrep which is part of the desktop search engine Strigi (Debian package strigi-utils). It searches tar.gz files as well as zip archives, Debian packages, and even Microsoft Word files. Example 6 shows how it works. Line by line you see the file name, and the according matches.

Example 6: Searching an archive using deepgrep

Searching Other Document Types

deepgrep covers a lot of file formats but has quite a few package dependencies. Instead you may have a look at pdfgrep and ssgrep , instead. pdfgrep is specialized for PDF documents, and ssgrep is for spreadsheets.

What I like about pdfgrep is both its simplicity in usage, and variety in terms of options. Matches are highlighted without the need to specify further arguments.

The option -n , which is shown in use below, helps to identify the page the pattern was discovered. In Example 7, each line consists of three data fields that are separated by a column — the file name, the page number of the match, and the extracted text from the match. If the output terminal supports colors the data fields and the matches are highlighted in different ways.

Example 7: Searching PDF documents

As mentioned above, ssgrep helps you to search spreadsheets. ssgrep abbreviates «spreadsheet grep», and is part of the Gnumeric tool. As the file format, both Open/Libre Office Calc and Gnumeric use gzip -compressed XML as their file format. Newer releases of Microsoft Excel could work as well, but I didn’t test. Figure 1 shows an example spreadsheet with sales data and four orders.

To identify the single cells that contain the term «NanoStation», ssgrep is called with the options -H and -n . -H outputs the file name as the first data field, and -n adds the location — the name of the spreadsheet, and the table position. See Example 8 below for the output.

The tools presented up to now are command line tools. To search Open/Libre Office documents you may use the graphical tool named «loook» (Debian package loook). Figure 2 shows the simple graphical user interface.

Conclusion

Searching data formats is complex, and can be an endless story. Several tools helps you to identify the relevant files easily. For a full list of commands for other data formats have a look at the given references below.

Further Reading

Axel Beckert, Frank Hofmann: Nadel im Datenhaufen. Suche in komprimierten Dateien und Archiven, LinuxUser 04/2012

Axel Beckert, Frank Hofmann: Mit Struktur. Suche in Datenformaten (Teil 1), LinuxUser 06/2012

Axel Beckert, Frank Hofmann: Durchgekämmt. Suche in Datenformaten (Teil 2), LinuxUser 07/2012

Acknowledgements

The author would like to thank Axel Beckert and Gerold Rupprecht for their support, and critics while preparing this article.

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Finding a File Containing a Particular Text String In Linux Server

Tutorial details
Difficulty level	Easy
Root privileges	No
Requirements	grep
Est. reading time	Less than 2 minutes

You need to use the grep command. The grep command or egrep command searches the given input FILEs for lines containing a match or a text string.

grep command syntax for finding a file containing a particular text string

The syntax is:
grep » text string to search » directory-path
grep [option] » text string to search » directory-path
grep -r » text string to search «directory-path
grep -r -H » text string to search » directory-path
egrep -R » word-1|word-2 » /path/to/directory
egrep -w -R » word-1|word-2 » directory-path
Let us see some common example on how to use grep to search for strings in files.

How to search and find all files for a given text string

In this example, search for a string called ‘redeem reward’ in all text (*.txt) files located in /home/tom/ directory, use:
$ grep «redeem reward» /home/tom/*.txt
OR
$ grep «redeem reward»

Task: Search all subdirectories recursively

You can search for a text string all files under each directory, recursively with -r option:
$ grep -r «redeem reward» /home/tom/
OR
$ grep -R «redeem reward» /home/tom/
Look for all files containing cacheRoot text on Linux:
grep -R cacheRoot /home/vivek/

Trying to find all files containing specific text on my Linux desktop

Task: Only display filenames

By default, the grep command prints the matching lines. You can pass -H option to print the filename for each match:
$ grep -H -r «redeem reward» /home/tom
Sample outputs:

To just display the filename use the cut command as follows:
$ grep -H -R vivek /etc/* | cut -d: -f1
Sample outputs:

Task: Suppress file names

The grep command shows output on a separate line, and it is preceded by the name of the file in which it was found in the case of multiple files. You can pass the -h option to suppress inclusion of the file names in the output:
$ grep -h -R ‘main()’

Task: Display only words

You can select only those lines containing matches that form whole words using the -w option. In this example, search for word ‘getMyData()’ only in

/projects/ dirctory:
$ grep -w -R ‘getMyData()’

Task: Search for two or more words

Use the egrep command as follows:
$ egrep -w -R ‘word1|word2’

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Task: Hide warning spam

grep command generate error message as follows due to permission and other issues:

No such file or directory
No such device or address
Permission denied

To hide all errors or warning message spam generated by the grep command, append 2>/dev/null to grep command. This will send and hide unwanted output to /dev/null device:
$ grep -w -R ‘getMyData()’

Task: Display matched text in color

Pass the —color option to the grep command display matched text/words in color on the terminal:

Fig.01: grep command in action with colors and hiding the warnings on screen

Task: Ignore case

Our final example ignore case distinctions in both the search PATTERN and the input files:
grep -i -R ‘word’ /path/to/dir
grep -i -r ‘income tax’

How do I find all files containing specific text on Linux?

The syntax is:
egrep ‘pattern’ -rnw /path/to/dir/
egrep ‘word1|word2’ -rnw /home/vivek/backups/

Finding text strings within files using grep

In this example search for lines starting with any lowercase or uppercase letter:
grep «^[a-zA-Z]» -rns

• -r – Recursive search
• -R – Read all files under each directory, recursively. Follow all symbolic links, unlike -r grep option
• -n – Display line number of each matched line
• -s – Suppress error messages about nonexistent or unreadable files
• -w – Only work on words i.e. search only those lines containing matches that form whole words
• -l – Show the name of each input file when match found
• -i – Ignore case while searching

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