There are a lot of ways to change the amount of white space (space and tab characters) in a line:
Berkeley systems have cat -s (25.10) to replace sets of two or more blank lines with single blank lines. If you don't have cat -s or need something different, look at article 34.18.
The crush (25.11) script removes all blank lines.
Use doublespace and triplespace (25.12) to double- and triple-space text.
The pushin (25.13) script replaces multiple white space characters with a single space. This can shorten long lines.
You can use sed to indent lines of text before printing (43.9). The offset (35.7) shell script does that more easily.
For other jobs, utilities like awk (33.11) and sed (34.24) will probably do what you want. You have to understand how to program them before you use them.
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