Answers to Frequently Asked Questions

# 4. Answers to Frequently Asked Questions

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Q1. How do I prevent the staircase effect?

A1. The staircase effect is caused by the way some printers expect lines to be terminated. Some printers want lines that end with a carriage-return/line-feed sequence (DOS-style) instead of the default line-feed sequence used for UNIX-type systems. The easiest way to fix this is to see if your printer can switch between the two styles somehow---either by flipping a DIP switch, or by sending an escape sequence at the start of each print job. To do the latter, you need to create a filter (see Q2 and Foster95b).

A quick fix is to use a filter on the command-line. An example of this might be

> `

>     $ cat thesis.txt | todos | lpr

> `

Q2. What is a filter?

A2. A filter is a program that reads from standard input (stdin), performs some action on this input, and writes to standard output (stdout). Filters are used for a lot of things, including text processing.

Q3. What is a magic filter?

A3. A magic filter is a filter that performs an action based on a file's type. For example, if the file is a plain, text file, it would simply print the file using the normal methods. If the file is a PostScript file, or any other format, it would print it using another method (ghostscript).

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