Insert control characters in text file

Note: NUL was originally intended as an ignorable filler character with no meaning. Especially convenient on paper tape, where a NUL equals no holes punched, it could be used to reserve space for new information or correcting errors.

ASCII even suggests NUL as a "time-waster" character to be added after a newline to accommodate mechanical devices where a carriage return works slowly.

Several programming languages use this convention. Indicates the beginning of a heading in a transmission. The heading can be terminated by STX. Later standards have dropped the explanation. It is not intended for marking a heading in a document. STX has two functions in a transmission: it 1 indicates the beginning of a text and 2 may terminate a heading see SOH. Terminates a text in a transmission. Note: ETX may be used to call for reply from a slave station after a message has been sent.

Indicates the conclusion of a transmission. The transmission may have contained one or more texts and associated heading s. Note: EOT can be used to end or abort a transmission. It can also be a reply to indicate inability to receive further messages. Requests a response from a remote station. The response may include station identification or status. Note: ACK can indicate that a slave station has received a message correctly and is ready to receive more.

Note: BEL is the only control character with an audible effect. It has been used to ring a bell indeed or produce a beep sound. A visual alarm is also possible. Note: Contrary to the standards, BS has been used as a combined "move back and delete" operation to remove the previous character.

This is not the standard meaning of BS, however. BS is defined as a non-destructive "move back" or "move left" operation, similar to a backspace in mechanical typewriters. On paper tape the result would be the previous character being completely punched out erased. BS followed by another character would strike two characters in the same position. Overstriking was a way to produce combined characters. A letter followed by BS followed by a diacritic symbol would produce an accented letter.

A boldface effect could be achieved by striking the same character several times at the same position. Overstriking was a useful option with printing devices, but displays hardly support it. With the advent of more capable character sets and formatting techniques overstriking can be considered outdated.

ASCII does not require overstriking capabilities and suggests that overstriking may be proscribed in the future. ISO explicitly forbids overstriking. Advances to the next pre-determined character position horizontal tab stop. HT could also be used as a skip function on punched cards. Even though the standards don't set a universal tab width, a typical fixed tab width is 8 columns.

Other tab widths, as well as custom tab positions, are used as well. HT is a simple method of data compression: a single character can represent several spaces in formatted text.

How the HT is treated in each application is another story. In windowing environments, there are three common alternative uses. This way the key has been extended to cover more uses than what HT was originally intended for.

The original name of HT is Horizontal Tabulation. LF has two alternative functions. It advances to the same character position on the next line move down , or optionally to the first position on the next line move to start of next line, i. Originally LF was a move-down. A newline option NL was added soon. Use of LF as a newline requires agreement between sender and recipient of data.

Universal agreement has not been reached. Note: LF, having two alternative functions, has been a major source of confusion. While LF was initially defined as a "move down" operator, standards began to allow LF as a newline too. As a result, operating systems differ in their definition of a newline. A newline is LF on Unix. Naturally, this caused an incompatibility. This did not solve the issue, resulting in IND being removed later.

The escape sequence for newline and LF is another source of confusion. Advances to the same character position on the next pre-determined line. VT has been used to jump down to the next pre-defined line when printing on a paper form. According to some sources, vertical tab stops were typically spaced 6 lines apart.

In modern use VT must be quite a rare character. It cannot be used directly on any terminal that I know of. Advances to the next form or page. Standards differ in what column the subsequent character position will be in. Note: FF has been used as "page break" in text files, "new page" on printers and "clear the screen" on displays.

The situation was originally unclear whether FF was just a "new page" operator or "new page, move to column 1". Note: The standard meaning of CR is "move to beginning of current line". This allows overprinting the line with new characters, which could be used to achieve underlining, for example. For advancing to the next line CR would be followed by LF. CR alone has been used as the newline character on some systems, such as Commodore and Apple, which use does not conform to the standards in question.

A non-printing LF was more suitable output while the printing head was returning, rather than striking a graphic symbol in the middle of the line. Used to extend the character set. SO may alter the meaning of the following bit combinations until an SI is reached. Between SI and SO, character positions decimal may represent additional characters that would not otherwise fit in the regular character set. Note: SO Shift Out is normal name of this control. In those standards, SO is used in 7-bit environments and LS1 in 8-bit environments.

It includes the use of escape sequences starting with ESC. SO has also been used on printers to select enlarged characters or another color. Used in conjunction with SO. It may reinstate the standard meanings of the characters following it. Note: SI Shift In is normal name of this control. In those standards, SI is used in 7-bit environments and LS0 in 8-bit environments. SI has also been used on printers to select condensed characters or to reset color.

Used to provide supplementary data transmission control functions. DLE changes the meaning of a limited number of following characters. Note: DLE is the "escape" character for transmission control. DLE can potentially be put in the front of a transmission control character TC1-TC10 to pass it through "as is" instead of controlling the current transmission. This is not always the case, though.

It is possible to create new transmission control sequences with DLE in a similar way ESC is used to create escape sequences for other purposes. Intended to turn on or start an ancillary device, to restore it to the basic operation mode see DC2 and DC3 , or for any other device control function. The name XON "transmit on" does not come from a standard, but it is commonly used.

Intended for turning on or starting an ancillary device, set it to a special mode restored via DC1 , or for any other device control function.

Intended for turning off or stopping an ancillary device. It may be a secondary level stop such as wait, pause, stand-by or halt restored via DC1. It can also perform any other device control function. An XOFF is issued to stop transmission when a device cannot accept more data. The name XOFF "transmit off" does not come from a standard, but it is commonly used. Pressing any key continues.

Intended to turn off, stop or interrupt an ancillary device, or for any other device control function. Note: NAK can be sent as a response to indicate inability to receive a message, or to request resending.

Used as "time-fill" in synchronous transmission. Sent during an idle condition to retain a signal when there are no other characters to send.

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I have an existing text file that is one long string. I would like to create a. I am not really sure how to do tilde replacement within a batch file because the tilde is a special character within the SET command for substrings.

The above accepts your input file as its argument, which means it could be as simple as a drag and drop job. The answers on How can you find and replace text in a file using the Windows command-line environment?

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Well, OK; you better go take care of that. Comments are closed. Scripting Forums. PowerShell Forums. PowerShell on TechCommunity. July 11th, I have an HTA which includes a text box where the user must enter a part number.

Part numbers must consist of a certain set of characters; how can I ScriptingGuy1 July 12, How can I use Windows PowerShell to retrieve the value of environment variables and the path to a special folder? ScriptingGuy1 July 13,