Regular Expressions 101

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An explanation of your regex will be automatically generated as you type.
Detailed match information will be displayed here automatically.
  • All Tokens
  • Common Tokens
  • General Tokens
  • Anchors
  • Meta Sequences
  • Quantifiers
  • Group Constructs
  • Character Classes
  • Flags/Modifiers
  • Substitution
  • A single character of: a, b or c
    [abc]
  • A character except: a, b or c
    [^abc]
  • A character in the range: a-z
    [a-z]
  • A character not in the range: a-z
    [^a-z]
  • A character in the range: a-z or A-Z
    [a-zA-Z]
  • Any single character
    .
  • Alternate - match either a or b
    a|b
  • Any whitespace character
    \s
  • Any non-whitespace character
    \S
  • Any digit
    \d
  • Any non-digit
    \D
  • Any word character
    \w
  • Any non-word character
    \W
  • Non-capturing group
    (?:...)
  • Capturing group
    (...)
  • Zero or one of a
    a?
  • Zero or more of a
    a*
  • One or more of a
    a+
  • Exactly 3 of a
    a{3}
  • 3 or more of a
    a{3,}
  • Between 3 and 6 of a
    a{3,6}
  • Start of string
    ^
  • End of string
    $
  • A word boundary
    \b
  • Non-word boundary
    \B

Regular Expression

/
/
gm

Test String

Substitution

Processing...

Code Generator

Generated Code

$re = '/\$([^{("\\\\\'\/])([a-zA-Z0-9_]*)([^}\/ \t\'"\n.\]:(=\\\\-]*)/m'; $str = 'amavis_permissions_status=$(find -H $amavis_state_dir -maxdepth 3 -a \\( \\! -user amavis -o \\! -group amavis \\)) if [[ -n $amavis_permissions_status ]] then _notify \'inf\' "Fixing $amavis_state_dir permissions" chown -hR amavis:amavis $amavis_state_dir else _notify \'inf\' "Permissions in $amavis_state_dir look OK" return 0 fi } function _fix_cleanup_clamav() { _notify \'task\' \'Cleaning up disabled Clamav\' rm -f /etc/logrotate.d/clamav-* rm -f /etc/cron.d/clamav-freshclam } function _fix_cleanup_spamassassin() { _notify \'task\' \'Cleaning up disabled spamassassin\' rm -f /etc/cron.daily/spamassassin } ########################################################################## # << Fix Stack ########################################################################## ########################################################################## # >> Misc Stack # # Description: Place functions that do not fit in the sections above here ########################################################################## function misc() { _notify \'taskgrp\' \'Starting Misc\' for _func in "${FUNCS_MISC[@]}" do if ! $_func then _defunc fi done } function _misc_save_states() { # consolidate all states into a single directory (`/var/mail-state`) to allow persistence using docker volumes statedir=/var/mail-state if [[ $ONE_DIR -eq 1 ]] && [[ -d $statedir ]] then _notify \'inf\' "Consolidating all state onto $statedir" local FILES=( /var/spool/postfix /var/lib/postfix /var/lib/amavis /var/lib/clamav /var/lib/spamassassin /var/lib/fail2ban /var/lib/postgrey /var/lib/dovecot ) for d in "${FILES[@]}" do dest="$statedir/$(echo "$d" | sed -e \'s/.var.//; s/\\//-/g\')" if [[ -d $dest ]] then _notify \'inf\' " Destination $dest exists, linking $d to it" rm -rf "$d" ln -s "$dest" "$d" elif [[ -d $d ]] then _notify \'inf\' " Moving contents of $d to $dest:" "$(ls "$d")" mv "$d" "$dest" ln -s "$dest" "$d" else _notify \'inf\' " Linking $d to $dest" mkdir -p "$dest" ln -s "$dest" "$d" fi done _notify \'inf\' \'Fixing /var/mail-state/* permissions\' chown -R clamav /var/mail-state/lib-clamav chown -R postfix /var/mail-state/lib-postfix chown -R postgrey /var/mail-state/lib-postgrey chown -R debian-spamd /var/mail-state/lib-spamassassin chown -R postfix /var/mail-state/spool-postfix fi } ########################################################################## # >> Start Daemons ########################################################################## function start_daemons() { _notify \'taskgrp\' \'Starting mail server\' for _func in "${DAEMONS_START[@]}" do if ! $_func then _defunc fi done } function _start_daemons_cron() { _notify \'task\' \'Starting cron\' \'n\' supervisorctl start cron } function _start_daemons_rsyslog() { _notify \'task\' \'Starting rsyslog \' \'n\' supervisorctl start rsyslog } function _start_daemons_saslauthd() { _notify \'task\' \'Starting saslauthd\' \'n\' supervisorctl start "saslauthd_${SASLAUTHD_MECHANISMS}" } function _start_daemons_fail2ban() { _notify \'task\' \'Starting fail2ban \' \'n\' touch /var/log/auth.log # delete fail2ban.sock that probably was left here after container restart if [[ -e /var/run/fail2ban/fail2ban.sock ]] then rm /var/run/fail2ban/fail2ban.sock fi supervisorctl start fail2ban } function _start_daemons_opendkim() { _notify \'task\' \'Starting opendkim \' \'n\' supervisorctl start opendkim } function _start_daemons_opendmarc() { _notify \'task\' \'Starting opendmarc \' \'n\' supervisorctl start opendmarc } function _start_daemons_postsrsd() { _notify \'task\' \'Starting postsrsd \' \'n\' supervisorctl start postsrsd } function _start_daemons_postfix() { _notify \'task\' \'Starting postfix\' \'n\' supervisorctl start postfix } function _start_daemons_dovecot() { # Here we are starting sasl and imap, not pop3 because it\'s disabled by default _notify \'task\' \'Starting dovecot services\' \'n\' if [[ $ENABLE_POP3 -eq 1 ]] then _notify \'task\' \'Starting pop3 services\' \'n\' mv /etc/dovecot/protocols.d/pop3d.protocol.disab /etc/dovecot/protocols.d/pop3d.protocol fi if [[ -f /tmp/docker-mailserver/dovecot.cf ]] then cp /tmp/docker-mailserver/dovecot.cf /etc/dovecot/local.conf fi supervisorctl start dovecot # TODO fix: on integration test # doveadm: Error: userdb lookup: connect(/var/run/dovecot/auth-userdb) failed: No such file or directory # doveadm: Fatal: user listing failed # if [[ $ENABLE_LDAP -ne 1 ]] # then # echo "Listing users" # /usr/sbin/dovecot user \'*\' # fi } function _start_daemons_fetchmail() { _notify \'task\' \'Starting fetchmail\' \'n\' /usr/local/bin/setup-fetchmail supervisorctl start fetchmail } function _start_daemons_clamav() { _notify \'task\' \'Starting clamav\' \'n\' supervisorctl start clamav } function _start_daemons_postgrey() { _notify \'task\' \'Starting postgrey\' \'n\' rm -f /var/run/postgrey/postgrey.pid supervisorctl start postgrey } function _start_daemons_amavis() { _notify \'task\' \'Starting amavis\' \'n\' supervisorctl start amavis } ########################################################################## # << Start Daemons ########################################################################## ########################################################################## # Start check for update postfix-accounts and postfix-virtual ########################################################################## function _start_changedetector() { _notify \'task\' \'Starting changedetector\' \'n\' supervisorctl start changedetector } # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! # ! CARE --> DON\'T CHANGE, unless you exactly know what you are doing # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! # shellcheck source=/dev/null . /usr/local/bin/helper_functions.sh if [[ ${DEFAULT_VARS["DMS_DEBUG"]} -eq 1 ]] then _notify \'taskgrp\' "" _notify \'taskgrp\' "#" _notify \'taskgrp\' "#" _notify \'taskgrp\' "# ENV" _notify \'taskgrp\' "#" _notify \'taskgrp\' "#" _notify \'taskgrp\' "" printenv fi _notify \'taskgrp\' "" _notify \'taskgrp\' "#" _notify \'taskgrp\' "#" _notify \'taskgrp\' "# docker-mailserver" _notify \'taskgrp\' "#" _notify \'taskgrp\' "#" _notify \'taskgrp\' "" register_functions check setup fix misc start_daemons _notify \'taskgrp\' "" _notify \'taskgrp\' "#" _notify \'taskgrp\' "# $HOSTNAME is up and running" _notify \'taskgrp\' "#" _notify \'taskgrp\' "" touch /var/log/mail/mail.log tail -fn 0 /var/log/mail/mail.log # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! # ! CARE --> DON\'T CHANGE, unless you exactly know what you are doing # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! exit 0 '; $subst = "${$1$2$3}"; $result = preg_replace($re, $subst, $str); echo "The result of the substitution is ".$result;

Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php