Regular Expressions 101

Pro

1st Alternative(?:hdd\s+\dtb hdd \dtb(?!\s+hdd)|(?<!hdd\s)\dtb hdd \dtb\s+hdd)(*SKIP)(*F)

Non-Capturing Group(?:hdd\s+\dtb hdd \dtb(?!\s+hdd)|(?<!hdd\s)\dtb hdd \dtb\s+hdd)

1st Alternativehdd\s+\dtb hdd \dtb(?!\s+hdd)

hddthe literal text hdd (case sensitive)

\s+any whitespace character, repeated at least once

\da digit

tb hdd the literal text tb hdd (case sensitive)

\da digit

tbthe literal text tb (case sensitive)

Negative Lookahead(?!\s+hdd)

\s+any whitespace character, repeated at least once

hddthe literal text hdd (case sensitive)

2nd Alternative(?<!hdd\s)\dtb hdd \dtb\s+hdd

Negative Lookbehind(?<!hdd\s)

hddthe literal text hdd (case sensitive)

\sany whitespace character

\da digit

tb hdd the literal text tb hdd (case sensitive)

\da digit

tbthe literal text tb (case sensitive)

\s+any whitespace character, repeated at least once

hddthe literal text hdd (case sensitive)

(*SKIP)acts like (*PRUNE), but the next unanchored match attempt starts where (*SKIP) was reached instead of at the next subject character

(*F)forces the current match attempt to fail at this position

2nd Alternative\dtb hdd \dtb

\da digit

tb hdd the literal text tb hdd (case sensitive)

\da digit

tbthe literal text tb (case sensitive)

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

Detailed match information will be displayed here automatically.

25 tokens

Regular Expression

(?:hdd\s+\dtb hdd \dtb(?!\s+hdd)|(?<!hdd\s)\dtb hdd \dtb\s+hdd)(*SKIP)(*F)|\dtb hdd \dtb

{sometext...} 1tb hdd 1tb hdd {sometext...}
{sometext...} 1tb hdd 1tb {sometext...}
{sometext...} hdd 1tb hdd 1tb {sometext...}
{sometext...} hdd 1tb hdd 1tb hdd {sometext...}

Substitution

{sometext...} 1tb hdd 1tb hdd {sometext...}
{sometext...} 1tb hdd 1tb {sometext...}
{sometext...} hdd 1tb hdd 1tb {sometext...}
{sometext...} hdd 1tb hdd 1tb hdd {sometext...}