Print only matched part

Extract IP addresses from log using Perl regex

grep -oP '\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}' access.log | sort -u
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grep15 commands
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grep

More grep commands

  • Invert match
    grep -v '^#' /etc/nginx/nginx.conf | grep -v '^\s*$'

    Remove comment and blank lines from a config file

  • Search only in file type
    grep -r --include='*.py' 'import os' /srv/app/

    Limit recursive search to .py files only

  • Exclude directories
    grep -r --exclude-dir='.git' --exclude-dir='node_modules' 'TODO' .

    Search recursively skipping vcs and dependency dirs

  • Print filename and line number
    grep -rn 'panic:' /var/log/app/

    Show file and line number for each match

  • ripgrep fast search
    rg 'TODO|FIXME|HACK' --type py -l

    List files containing TODO/FIXME/HACK in Python files

all 15 grep commands