Grep command in linux explained
Grep command used for search files and search pattern. (Find Text in Files).
grep command stands for “global regular expression print
grep [options] pattern [files]
Options Description
-c : counts the frequency only
-h : Display the matched lines, but do not display the filenames.
-i : case insensitive Ignores, case for matching
-l : filenames only.(imp)
-n : line number if word in a file
-v : lines that are not matched with the keyword
-e exp : Specifies expression with this option. Can use multiple times.
-f file : takes the file patterns
-E : Treats pattern as an extended regular expression (ERE)
-w : prints whole words in a file
-o : Print only matched words per line
Expressions
Start ^
End $
grep “^linux” mynewfile.txt
grep “ux$” mynewfile.txt
$grep –e “admin” –e “admin” –e “admin” newfile.txt
$grep –f newfile.txt mynewfile.txt
Finding a text in list of files in a directory.
grep ‘word’ file1 file2 file3
grep -n ‘root’ /etc/passwd
grep –color root /etc/passwd
Grep From Files and Display the File Name On Linux
grep -l “string” filenamegrep -l root /etc/*
Searching a String / word in files & directories
root@instance-1:/etc/nginx# grep -nr ‘cache-control’ .
./conf.d/global.config:62:add_header cache-control “max-age=31536000”;
./conf.d/expires.global:5:add_header cache-control: max-age=31536000;
grep command to search string word in file
root@-s-4vcpu-8gb-blr1-01:~# grep root /etc/passwd
root:x:0:0:root:/root:/bin/bash
grep WP_CACHE_KEY_SALT /var/www/html/yoursite.com/wp-config.php
all files containing string
grep -R containing text /home/user/
grep ‘string1 string2’ filename
finding a file containing a particular text string
grep “find me in home” /home/tom/*.txt
grep “find me anywhere in text files “~/*.txt
use grep recursively
grep -R “192.168.0.1” /etc/
grep -R ‘string’ dir/
grep -R ‘expires’ /etc/nginx/
root@instance-1:/etc/nginx# grep -R ‘expires’ /etc/nginx/
/etc/nginx/rocket-nginx/default.conf: expires 30d;
/etc/nginx/rocket-nginx/default.conf: expires 30d;
/etc/nginx/rocket-nginx/default.conf: expires 30d;
/etc/nginx/rocket-nginx/rocket-nginx.tmpl: expires 30d;
/etc/nginx/rocket-nginx/rocket-nginx.tmpl: expires 30d;
/etc/nginx/rocket-nginx/rocket-nginx.tmpl: expires 30d;
/etc/nginx/sites-enabled/rajuginne: # Directives to send expires headers and turn off 404 error logging.
/etc/nginx/sites-enabled/rajuginne: expires 24h;
/etc/nginx/conf.d/default.conf: expires 31536000s;
/etc/nginx/conf.d/default.conf: expires 3600s;
/etc/nginx/conf.d/default.conf: expires 31536000s;
/etc/nginx/conf.d/headers.conf:#add_header expires $expires;
/etc/nginx/conf.d/headers.conf:map $sent_http_content_type $expires {
/etc/nginx/conf.d/browsercaching.confg: expires 3600s;
/etc/nginx/conf.d/expires.global: expires 365d;
/etc/nginx/conf.d/global2.config: expires max;
/etc/nginx/rocket-nginx/default.conf: expires 30d;
/etc/nginx/rocket-nginx/default.conf: expires 30d;
/etc/nginx/rocket-nginx/default.conf: expires 30d;
/etc/nginx/rocket-nginx/rocket-nginx.tmpl: expires 30d;
/etc/nginx/rocket-nginx/rocket-nginx.tmpl: expires 30d;
/etc/nginx/rocket-nginx/rocket-nginx.tmpl: expires 30d;
/etc/nginx/sites-enabled/rajuginne: # Directives to send expires headers and turn off 404 error logging.
/etc/nginx/sites-enabled/rajuginne: expires 24h;
/etc/nginx/conf.d/default.conf: expires 31536000s;
/etc/nginx/conf.d/default.conf: expires 3600s;
/etc/nginx/conf.d/default.conf: expires 31536000s;
/etc/nginx/conf.d/headers.conf:#add_header expires $expires;
/etc/nginx/conf.d/headers.conf:map $sent_http_content_type $expires {
/etc/nginx/conf.d/browsercaching.confg: expires 3600s;
/etc/nginx/conf.d/expires.global: expires 365d;
/etc/nginx/conf.d/global2.config: expires max;
grep -R ‘add_header’ /etc/nginx/
grep -nr ‘ssl’ .
t@instance-1:/etc/nginx# grep -nr ‘ssl’ .
./nginx.conf:38: #ssl_protocols TLSv1 TLSv1.1 TLSv1.2; # Dropping SSLv3, ref: POODLE
./nginx.conf:39: #ssl_prefer_server_ciphers on;
./rocket-nginx/README.md:153:**<a name=’faq_ssl’>Will Rocket-Nginx work if my we bsite uses a SSL certificate (https) ?</a>**
./sites-enabled/f.in.conf:5:#ssl on;
./sites-enabled/ff.in.conf:6:ssl_certificate /etc/nginx/ssl/ssc.pem;
./sites-enabled/ff.in.conf:7:ssl_certificate_key /etc/nginx/ssl/ssc.key;
./sites-enabled/ffff.in:5:#listen 443 ssl http2;
./sites-enabled/.in:8:#include /etc/letsencrypt/options-ssl-nginx. conf;
./nginx.conf:38: #ssl_protocols TLSv1 TLSv1.1 TLSv1.2; # Dropping SSLv3, ref: POODLE
./nginx.conf:39: #ssl_prefer_server_ciphers on;
./rocket-nginx/README.md:153:**<a name=’faq_ssl’>Will Rocket-Nginx work if my we bsite uses a SSL certificate (https) ?</a>**
./sites-enabled/f.in.conf:5:#ssl on;
./sites-enabled/ff.in.conf:6:ssl_certificate /etc/nginx/ssl/ssc.pem;
./sites-enabled/ff.in.conf:7:ssl_certificate_key /etc/nginx/ssl/ssc.key;
./sites-enabled/ffff.in:5:#listen 443 ssl http2;
./sites-enabled/.in:8:#include /etc/letsencrypt/options-ssl-nginx. conf;
The dot at the end searches the current directory. Meaning for each parameter:
-n Show relative line number in the file
‘yourString*’ String for search, followed by a wildcard character
-r Recursively search subdirectories listed
. Directory for search (current directory)
cd /etc/nginx/sites-enabled#
grep -nr ‘ssl’ .
./eaadharcard.co.in.conf:8: ssl on;
./eaadharcard.co.in.conf:9: ssl_certificate /etc/nginx/ssl/eaadharcard.co.in.pem;
./eaadharcard.co.in.conf:10: ssl_certificate_key /etc/nginx/ssl/eaadharcard.co.in.key;
./employmentnewsdaily.in:5: ssl on;
root@instance-1:~# grep . /proc/sys/net/ipv4/tcp*mem
/proc/sys/net/ipv4/tcp_mem:45525 60702 91050
/proc/sys/net/ipv4/tcp_rmem:4096 131072 6291456
/proc/sys/net/ipv4/tcp_wmem:4096 16384 4194304
root@instance-1:~#/etc/nginx/sites-enabled# grep -nr ‘raazkumar.com‘ .
linux find a file in a directory
The find command can only filter the directory hierarchy based on a file’s name and metadata. If you need to search based on the file’s content, use a tool like grep. Consider the following example:
find . -type f -exec grep “example” ‘{}’ \; -print
find command to find a file in a directory
find /path option filename
i want to ind newrelic.ini file this directory
find /etc/php/7.4/fpm/conf.d/ newrelic
ls -l /etc/php/7.4/fpm/conf.d/
2nd way
cd /etc/php/7.4/fpm/conf.d/
grep newrelic
/etc/php/7.4/fpm/conf.d
