textslave.com

Open Textslave in your browser, paste your text, and go to the Duplicate lines section. Choose Remove to delete repeated lines or Extract to keep only the lines that appear more than once. Leave "But do not collapse them" unchecked for a clean, deduplicated list; check it when you want to see every repeated occurrence. Use Preview to confirm the result before Save.

What the Duplicate lines section does

The Duplicate lines section contains two separate operations, each with its own preview and save controls:

Both operations share the same option set, so once you understand one, the other behaves the same way.

Step-by-step: removing duplicate lines

1. Paste your text into the Textslave input area. Each line should be a separate entry, since the tool works line by line.
2. Go to Duplicate lines → Remove.
3. Decide on the "But do not collapse them" checkbox.
   • Unchecked (default): duplicates are collapsed — each unique line appears once in the output.
   • Checked: duplicates are not collapsed — repeated lines stay as separate occurrences, so the output preserves the original repetition rather than reducing it to one copy.
4. Optionally set advanced options (see the next section) to limit which lines are treated as candidates.
5. Click Preview to see the result without committing.
6. Click Save when the preview looks right.

What "But do not collapse them" actually changes

This is the option most people misread. Think of it as controlling whether repeated lines are merged into a single copy:

• A list like apple / apple / banana with collapsing on becomes apple / banana.
• The same list with "do not collapse" checked keeps the repeated apple entries as they are, so the operation does not reduce them to one line.

If your goal is a clean unique list, leave it unchecked. If you need to preserve the original count of repeated lines — for example, when the repetition itself carries meaning — check it.

Step-by-step: extracting duplicate lines

1. Paste your text.
2. Go to Duplicate lines → Extract.
3. Choose whether to "But do not collapse them" — the same logic applies: unchecked gives you the duplicated lines in collapsed form, checked preserves each repeated occurrence.
4. Preview, then Save.

Extract is the faster route when you don't want to delete anything but need to see which lines repeat — useful for checking a mailing list, a product SKU list, or a set of IDs for accidental repeats.

Narrowing the operation with advanced options

Both Remove and Extract offer the same advanced filters, so you can target only part of your text instead of the whole document.

Line-matching conditions

Limit the operation to lines that are:

• equal to a string
• different from a string
• containing a string
• lacking a string

Position filters

Apply the match everywhere, at the start, or at the end of the line.

For example, if you only want to deduplicate lines that contain @example.com, set the condition to containing and enter that string. Lines without it are left untouched, which is handy when one file mixes several kinds of records.

Verifying the result before you save

Always use Preview first. Check three things:

1. Count — does the number of lines match what you expected after removal or extraction?
2. Order — are the remaining lines in the order you need?
3. Edge cases — did lines that differ only by trailing spaces or capitalization get treated as duplicates? The tool compares text lines as written, so near-identical lines may not be caught. If that matters, clean whitespace first with the Whitespaces & Tabs tools, then run the duplicate operation.

Common snags

• Nothing was removed. Your "duplicates" probably differ by whitespace or case. Run Whitespaces & Tabs → Replace multiple whitespaces first, then retry.
• Too much was removed. Check whether "But do not collapse them" was left unchecked when you wanted every occurrence kept, or whether an advanced filter was broader than intended.
• Only some lines were affected. An advanced condition (equal to / containing / at the start, etc.) is still active — clear it and preview again.
• Blank lines remain. Duplicate handling doesn't target empty lines; use Remove Empty line for those, including the option to also catch lines made only of whitespace.

Once the preview matches your intent, click Save to apply the transformation to your text.

Paste your text into Textslave's Newline section, choose the operation you need — remove all newlines, replace them with a string, insert them at a fixed interval or around a word, or word-wrap by character count — then use Preview to check the result before saving. All five operations share the same advanced line filters, so you can limit the change to lines that are equal to, different from, containing, or lacking a given string, or that start or end with it. The tool runs in the browser and needs no setup beyond having your text ready.

The five Newline operations at a glance

Each operation has its own Preview and Save controls, and each carries the same advanced options block for filtering which lines are processed.

Removing newlines

Use Remove all when you want multi-line content — a list copied from a spreadsheet, wrapped paragraphs from a PDF, a column of addresses — collapsed into a single line. Paste the text, run the operation, preview, and save. Because the tool only strips line breaks, spacing inside each line is untouched; if the joined result looks cramped, run the Whitespaces & Tabs section afterward to normalize repeated spaces.

Replacing newlines with a chosen string

Replace newline takes whatever you type in the replacement field and puts it where each line break was. Common choices are a single space (to reflow wrapped text into paragraphs), a comma plus space (to turn a column into an inline list), or a pipe character for delimited output. The replacement is literal text, so you can enter multi-character strings, not just single symbols.

Adding newlines

Three separate operations cover insertion:

• Add a newline each takes a character count and breaks the text at that interval — useful for chunking a long unbroken string into fixed-width segments.
• Add a newline after / before targets a specific word, placing the break on the chosen side of every occurrence.
• Word wrap also takes a character count but wraps at that width, which suits preparing text for a fixed-width display or a plain-text document with a line-length limit.

If you only want breaks around some occurrences of a word rather than all of them, the advanced filters below let you restrict the operation to matching lines.

Filtering which lines are affected

Every Newline operation includes an advanced options block with the same controls: process only text lines that are equal to, different from, containing, or lacking a string, with the match applied everywhere, at the start, or at the end. This is what makes the tool practical on mixed content. For example, if a pasted log has header lines you want to keep intact and data lines you want joined, filter to the lines lacking the header prefix and apply Remove all only to those.

Verifying before you commit

Preview shows the transformed text before anything is saved, so check three things: that the line count matches what you expected, that filtered-out lines are unchanged, and that the replacement string appears where line breaks used to be. If the preview is wrong, adjust the filter or the character count and preview again — nothing is committed until you save.

Common snags

• Empty lines survive Remove all as blank space. If the source had double line breaks, removing newlines can leave gaps; run Remove empty lines in the Duplicate lines section, which also has an option to include lines containing only whitespace.
• Character counts include spaces. When adding newlines every N characters, spaces count toward N, so the visible break points may not align with word boundaries.
• Filters are line-based. They select whole lines to process or skip; they do not edit parts of a line. For partial-line edits, use the Substring or Word operations in the same section.
• Replacement text is not escaped. Whatever you type is inserted as-is, so avoid characters you don't want appearing literally in the output.

Textslave is a browser-based text transformer that handles common cleanup and reformatting jobs: removing or replacing newlines, normalizing whitespace and tabs, deduplicating lines, stripping empty lines, and applying line-level add, replace, split, and substring edits. It suits anyone pasting messy text — exported lists, log snippets, spreadsheet columns, scraped data — who needs predictable, rule-based changes rather than manual editing. The site describes itself as online and free; no pricing or login details are stated in the available material, so treat access terms as unconfirmed until you open the tool.

How the tool is organized

Every operation follows the same pattern: choose an operation, set its options, optionally narrow which lines it applies to, then preview before saving. That consistent structure is the main thing to learn — once you understand one panel, the rest work the same way.

The advanced options shared across operations let you restrict an action to lines that are equal to, different from, containing, or lacking a given string, applied everywhere, at the start, or at the end. This is what turns a blunt global replace into a targeted edit.

Normalizing newlines, whitespace, and tabs

These are the first tools to reach for when text arrives with broken line breaks or irregular spacing.

Newline operations

The Newline section covers four distinct jobs:

• Remove all newlines — collapses multi-line text into one continuous block.
• Replace newline — substitutes line breaks with a string of your choice (a space, a comma, a pipe).
• Add a newline each N characters — inserts breaks at a fixed interval, useful for wrapping long unbroken strings.
• Add a newline after/before a word — breaks lines at a specific token.
• Word wrap — wraps at a chosen character count.

The distinction between "add a newline each N characters" and "word wrap" matters: the first cuts at an exact position regardless of word boundaries, the second is intended for readable wrapping. If you are preparing text for display, word wrap is usually the safer choice; if you need fixed-width records, use the character-interval option.

Whitespace and tabs

Two operations handle spacing:

• Replace multiple whitespaces with a single character — the standard fix for text that has been double-spaced or indented inconsistently.
• Replace tabs with a chosen string — converts tab-delimited content into comma- or pipe-separated form.

Run whitespace normalization before deduplication. Two lines that look identical may differ only by trailing spaces, and collapsing whitespace first makes duplicate detection reliable.

Tidying lists: duplicates and empty lines

The Duplicate lines section splits into two opposite actions, and choosing the wrong one is the most common mistake:

Both offer a "do not collapse them" option, which preserves the original grouping rather than merging repeated entries into a single position — relevant when order carries meaning.

Separately, Remove empty lines deletes blank rows, with an option to also treat whitespace-only lines as empty. Enable that option whenever text has passed through a system that leaves invisible padding, or you will keep lines that look blank but are not.

The Text line operation removes all text lines under the same line-matching conditions, which is useful for filtering a list down to nothing but the entries you want to discard.

Line-level edits: add, replace, split, substring

These operations work per line, which is where Textslave differs from a plain find-and-replace.

• Substring — for each line, remove the part after or before a word, with options to target a specific occurrence (the ° occurrence), leave lines without the delimiter untouched, and keep the divider itself.
• Word — remove a specified occurrence of a word from each line.

A concrete example: you have exported rows like ID-1042 | [email protected] | active and want only the email. Using Substring to remove everything before the first | and everything after the second, with "keep the divider" off, leaves clean addresses — while lines missing a delimiter stay intact instead of being silently mangled.

The Split capability in the site's keyword set pairs with these: splitting text into lines or segments is typically the step before applying line-level rules.

Preview before you save

Every operation includes a Preview and a Save control. Preview shows the result of your settings against the current text before anything is committed. Because most of these operations are destructive — removed characters are not recoverable from the output — the working habit is:

1. Paste the text.
2. Configure one operation.
3. Preview and check the first and last few lines, plus any edge cases (blank lines, lines without the target string).
4. Save, then move to the next operation.

Chain operations in a deliberate order: normalize whitespace → remove empty lines → deduplicate → apply line-level edits. Doing deduplication before whitespace cleanup, or substring extraction before removing blanks, tends to produce leftovers you then have to fix by hand.

When Textslave is the right fit — and when it isn't

Use it when the transformation can be expressed as a rule over lines or characters: cleaning pasted lists, converting delimiters, wrapping text, filtering rows by content. It is fast and requires no setup.

It is a weaker fit when the change depends on structure across lines — parsing nested data, validating formats, or transforming based on relationships between fields. For those, a script or spreadsheet formula gives you checks that a preview pane cannot. And since the available material does not document pricing tiers or account requirements, confirm access terms on the site itself if you plan to rely on it for recurring work.

Open Textslave and scroll to the Whitespaces & Tabs section. It contains two separate operations: Replace multiple whitespaces and Replace tab. Each has its own replacement input box, its own Preview button, and its own Save button. To collapse runs of spaces into one space, enter a single space in the "Replace multiple whitespaces with" field and click Preview. To convert tab characters to something else, enter the target character or string in the "Replace tabs with" field and preview the result. Nothing is applied to your text until you click Save, so you can inspect the output first.

Replace multiple whitespaces

This operation targets consecutive whitespace characters and replaces the whole run with the string you supply.

1. Paste or type your text into the Textslave input area.
2. In Whitespaces & Tabs, find Replace multiple whitespaces.
3. Type the replacement into the field labelled "Replace multiple whitespaces with". A single space is the usual choice when you want to normalise spacing.
4. Click Preview to see the transformed text.
5. If the result looks right, click Save to keep it.

The practical effect: a line like Name: John Smith becomes Name: John Smith when you replace with one space. Runs of spaces, and mixed runs of spaces and tabs, are treated as a single block and replaced once.

Choosing the replacement value

Preview first when you use an empty or unusual replacement, because the result can be hard to reverse by eye.

Replace tab

This is a separate operation from the whitespace collapse. It finds tab characters and substitutes the string you provide.

1. Locate Replace tab in the same section.
2. Enter the replacement in the "Replace tabs with" field — for example a single space, a comma, or a pipe character.
3. Click Preview.
4. Click Save when satisfied.

Use this when your text came from a spreadsheet or a fixed-width source and you want tab-separated columns turned into something readable, such as comma-separated values. If your text mixes tabs and spaces and you want everything normalised, run Replace tab first (converting tabs to spaces), then run Replace multiple whitespaces to collapse the resulting runs.

Filtering which lines are processed with advanced options

Both operations include an Use advanced options control. It lets you restrict the change to certain lines instead of the whole text. The available line conditions are:

• lines equal to a string
• lines different from a string
• lines containing a string
• lines lacking a string

You also choose where the string must appear: everywhere, at the start, or at the end.

For example, if only header rows contain a tab you want converted, set the condition to lines containing the header text, choose at the start, then run Replace tab. Lines that do not match are left untouched. This is the main safeguard against a global replace damaging parts of the text you meant to keep.

Verify before you save

Preview is the verification step. Compare the preview against the original for:

• lines where spacing carried meaning, such as indented code or aligned columns
• blank lines, which may disappear if they consisted only of spaces
• the boundaries of your filter, to confirm only intended lines changed

If the preview is wrong, adjust the replacement string or the advanced options and preview again. Save commits the result.

Common snags

• Indentation lost. Collapsing whitespace destroys leading indentation. If the text is code or an outline, filter to specific lines or skip this operation.
• Tabs converted but spaces remain. Run Replace tab before Replace multiple whitespaces, not after.
• Nothing changed. Check whether advanced options are active with a condition that matches no lines, and check that the replacement field is not identical to what is being replaced.
• Empty replacement behaves unexpectedly. Preview an empty replacement carefully; some tools treat it as "delete the match" and others ignore it.

Before you start

Keep a copy of the original text. These operations are one-way in the editing session, and a broad replace can remove formatting you did not notice until later. Paste into a scratch document first if the text is important, and only apply Save to the copy you are willing to change.

The web (World Wide Web) is a system of interlinked documents and resources, accessed over the internet using browsers and identified by URLs. It is one service that runs on top of the internet, not the internet itself. This explanation covers the core building blocks, what happens when a page loads, and how to tell "web" apart from "internet," "browser," and "search engine."

Web vs. internet vs. browser vs. search engine

These terms get used interchangeably, but they describe different things:

A useful analogy: the internet is the road system, the web is one type of traffic that travels on it, the browser is your car, and a search engine is a directory that tells you which roads lead where.

Email, video calls, and many mobile apps also use the internet but are not the web. Email, for instance, relies on its own protocols (like SMTP) rather than web pages.

The core building blocks of the web

URLs

A URL (Uniform Resource Locator) is the address of a resource on the web. A typical URL has parts that each do a job:

https://www.example.com/products/item?id=42

• https — the protocol (how to communicate)
• www.example.com — the domain (which server to contact)
• /products/item — the path (which resource on that server)
• ?id=42 — a query string (extra parameters)

HTTP and HTTPS

HTTP (Hypertext Transfer Protocol) is the set of rules browsers and servers use to exchange requests and responses. HTTPS is the same protocol wrapped in encryption (TLS), so the data can't be read or altered in transit. Most sites today use HTTPS, and browsers flag plain HTTP as "not secure."

Browsers

A browser turns code into the pages you see. It sends requests, receives files (HTML, CSS, JavaScript, images), and renders them into a visual layout. It also manages cookies, caching, and security warnings.

Web servers

A web server is a computer (and the software on it) that stores web content and responds to requests. When you visit a page, your browser asks a server for files, and the server sends them back.

What happens when you load a page

1. You enter a URL or click a link. The browser reads the address.
2. DNS lookup. The domain name (like example.com) is translated into an IP address so the browser knows which server to contact.
3. Connection. The browser opens a connection to that server, using HTTPS if available.
4. Request. The browser sends an HTTP request for the specific resource.
5. Response. The server returns the requested files and a status code (for example, 200 for success, 404 for not found).
6. Rendering. The browser parses HTML, applies CSS for styling, runs JavaScript for interactivity, and draws the page.
7. Follow-up requests. The page may request additional resources — images, fonts, scripts — before it's fully loaded.

If any step fails, you see an error: a DNS failure means the domain couldn't be resolved; a timeout means the server didn't respond; a 404 means the server responded but the resource wasn't there.

Where the web fits in everyday use

The web is what you're using when you:

• Open a site in a browser to read, shop, or log in
• Follow a link from an email or message
• Use a web app (a service that runs in the browser rather than as an installed program)
• Watch a video embedded on a page

It is not what you're using when you:

• Send or receive email through a mail client
• Make a phone or video call over the internet
• Use an installed mobile app that talks to its own servers

Those still depend on the internet, but they don't require a browser or web pages.

Common confusions, cleared up

• "The web is down." Usually a specific site or your connection is down, not the entire web.
• "I found it on the internet." If you found it through a browser and a URL, you found it on the web.
• "My browser is the internet." The browser is a tool for accessing the web; the internet is the underlying network.
• "A search engine is the web." A search engine is one website among many that helps you navigate the web.

Quick reference

• Web = linked documents and resources accessed via browsers over the internet.
• Internet = the global network that carries many services, including the web.
• Browser = software that requests and displays web content.
• URL = the address of a web resource.
• HTTP/HTTPS = the rules for exchanging web requests and responses; HTTPS adds encryption.
• Web server = the machine that stores and serves web content.

Understanding these distinctions makes it easier to describe problems accurately, choose the right tools, and follow technical instructions without mixing up the layers.