When there is more than one file to search it will display file name by default. Consider the following grep command:
grep "word" filename grep root /etc/*
Sample outputs:
/etc/bash.bashrc: See "man sudo_root" for details. /etc/crontab:17 * * * * root cd / && run-parts --report /etc/cron.hourly /etc/crontab:25 6 * * * root test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.daily ) /etc/crontab:47 6 * * 7 root test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.weekly ) /etc/crontab:52 6 1 * * root test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.monthly ) /etc/group:root:x:0: grep: /etc/gshadow: Permission denied /etc/logrotate.conf: create 0664 root utmp /etc/logrotate.conf: create 0660 root utmp
The first name is file name (e.g., /etc/crontab, /etc/group). The -l option will only print filename if the match found by the grep:
grep -l "string" filename grep -l root /etc/*
Sample outputs:
/etc/aliases /etc/arpwatch.conf grep: /etc/at.deny: Permission denied /etc/bash.bashrc /etc/bash_completion /etc/ca-certificates.conf /etc/crontab /etc/group
You can suppress normal output; instead print the name of each input file from which no output would normally have been printed:
grep -L "word" filename grep -L root /etc/*
Sample outputs:
/etc/apm /etc/apparmor /etc/apparmor.d /etc/apport /etc/apt /etc/avahi /etc/bash_completion.d /etc/bindresvport.blacklist /etc/blkid.conf /etc/bluetooth /etc/bogofilter.cf /etc/bonobo-activation /etc/brlapi.key
How to display filename before matching line in grep
By default grep display filename if you provide multiple filenames. For example:
grep 'foo' file1 file2
grep '192.168.2.254' /etc/hosts /etc/resolv.conf
grep -n '192.168.2.254' /etc/hosts /etc/resolv.conf
####################################################
## Always show filename headers with output lines.##
## Works with BSD/macOS/GNU/Linux grep version ##
####################################################
grep -H 'search-word' filename1 filename2
grep '192.168.2.254' /etc/hosts /dev/null
##########################
### gnu/Linux grep only ##
##########################
grep --with-filename 'foo' file1 file2
grep --with-filename '192.168.2.253' /etc/{hosts,resolv.conf}
Linux grep display filename before matching line
grep show filename before matching line
In this example, I need to search for ‘http://www.cyberciti.biz’ in all files and display matched filenames only, run:
grep -l -R 'http://www.cyberciti.biz'
Now replace all occurrences of ‘http://www.cyberciti.biz’ with ‘https://www.cyberciti.biz’ using the sed command:
## get filenames ## files=$(grep -l -R 'http://www.cyberciti.biz' . ) echo "$files" ## replace using sed ## for f in $files do sed -i 's+http://www.cyberciti.biz+https://www.cyberciti.biz+g' "$f" done
Conclusion – Grep from files and display the file name
Let us summaries all the grep command option in Linux or Unix:
- grep -l 'word' file1 file2 : Display the file name on Linux and Unix instead of normal output
- grep -L 'string' file1 file2 : Suppress normal output and show filenames from which no output would normally have been printed
- grep -n 'string' filename : Force grep to add prefix each line of output with the line number within its input file
- grep --with-filename 'word' file OR grep -H 'bar' file1 file2 file3: Print the file name for each match
- How To Use grep Command In Linux / UNIX
- Regular Expressions In grep
- Search Multiple Words / String Pattern Using grep Command
- Grep Count Lines If a String / Word Matches
- Grep From Files and Display the File Name
- How To Find Files by Content Under UNIX
- grep command: View Only Configuration File Directives
🐧 13 comments so far... add one ↓
| Category | List of Unix and Linux commands |
|---|---|
| File Management | cat |
| Firewall | Alpine Awall • CentOS 8 • OpenSUSE • RHEL 8 • Ubuntu 16.04 • Ubuntu 18.04 • Ubuntu 20.04 |
| Network Utilities | dig • host • ip • nmap |
| OpenVPN | CentOS 7 • CentOS 8 • Debian 10 • Debian 8/9 • Ubuntu 18.04 • Ubuntu 20.04 |
| Package Manager | apk • apt |
| Processes Management | bg • chroot • cron • disown • fg • jobs • killall • kill • pidof • pstree • pwdx • time |
| Searching | grep • whereis • which |
| User Information | groups • id • lastcomm • last • lid/libuser-lid • logname • members • users • whoami • who • w |
| WireGuard VPN | Alpine • CentOS 8 • Debian 10 • Firewall • Ubuntu 20.04 |
for i in `ls` ; do
grep -q “whatever” $i && echo $i
done
Why ls? It will fail when you have file names with white spaces. A better way is to use wild cards:
what about
grep -rI “whatever” ./ | cut -d: -f1 | sort -u
nb it will fail on file containing “:” such as some perl man pages but…
…Or just add some proper form
for i in `ls` ; do
grep -q “whatever” “$i” && echo “$i”
done
or if you need to search all file and subdirs within a dir you can run the commands above. Just replace `ls` with `find . -type f`.
Or better yet, use xargs.
find . -type f | xargs grep htmlIf you want to deal with spaces etc…
find . -type f | xargs -I {} grep -H foo "{}"Dealing with space with a shorter form
find . -type f -print0 | xargs -0 grep foo
I agree, find is working great for me.
find -name *.log -uid 1000
You can find files only owned by uid. Nifty feature.
How do I grep if i am looking for a specfic percentage?
grep -w “68%-100% /usr/local/stage”
thanks in advance
ls | while read FILE; do echo “$FILE” done;
This handles whitespace and other nasties nicely.
how can i grep
CA
from filename AUZ_CA_EL.txt
cat AUZ_CA_EL.txt | grep “CA”
how do I know the location and file name form the result that grep shows?
I use command like cat * | grep
Now what I need is the location of the file name along withe the grep result.
Help anyone
THX for the “$FILE” solution! Worther than 100 webpages!