less (Unix)
| Less
|
|
|---|---|
 Less, X-Terminal |
|
| Basic data
|
|
| developer | Mark Nudelman |
| Current version |
551 ( June 11, 2019 ) |
| operating system | DOS , Linux , OS / 2 , Solaris , Windows , etc. a. |
| programming language | C. |
| category | System application |
| License | dual licensing ( GPL 3+ and BSD-like Less license, thus free software ) |
| German speaking | No |
| www.greenwoodsoftware.com/less | |
less ( English for less ) is a Unix - command-line utility for paging Consider ( pager ) of text files . Using the shell script lesspipe.sh , which is only lesspipe in Debian derivatives , other file formats can be displayed in addition to text files. By pressing the v key , a file opened in less can be loaded into an editor and edited with it. After closing the editor, the changed content of the files is displayed in less . less outputs data tailored to the terminal size, whereby the file can be scrolled with various buttons .
syntax
The syntax of less is similar to many other command line programs:
less [-Option] <Dateiname>
By entering less --helpin the command line, a help page can be viewed in which the available call options are also listed.
prehistory
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more ( English for more ) is an older command for viewing text files in Unix. It outputs the text page by page on the command line , scrolling by pressing a key.
In contrast to the less command inspired by it , more was only able to scroll forward in the text, but not backward. This was a handicap in the work, whereupon less was developed. The name came about because one wanted a more with back (English backwards more ); in a broader sense less than more , that is, less ( less ).
Because on some Linux distributions more an alias for less is, is a common joke less is more ( less is more ).
history
In the early 1980s, the tools that came with the operating systems were too uncomfortable for "less" author Mark Nudelman. The vi text editor was not able to view log files because it could not manage the huge file sizes. The problem that the author saw in the more system tool he was using at the time was that the log files could only be viewed forwards , but the entries in the logs responsible for error messages preceded the error messages. But scrolling back was not possible with more .
Nudelman and his colleagues often complained about this problem that backwards more (English backwards more ) would be sought, or less (English less ). From this play on words, whose exact originator is unknown among colleagues, the name of the tool less , which was soon developed and completed in 1983, arose . After using and developing the software in-house, the author decided that less was useful enough to publish. In May 1985, for example, he made the first version of less available on Usenet , in what was then the newsgroup net.sources , under a free license.
Less does not use minor versions or the like in its version numbers . Instead, the version number is simply incremented with each new release. Version 409 is the 409th version of less.
Web links
- Web presence of the GNU variant
-
less(1): opposite of more - Debian GNU / Linux Executable programs or shell commands man page -
less(1): less, more - view files - OpenBSD General Commands Manual
Individual evidence
- ↑ Mark Nudelman: less-551 released for general use . June 11, 2019 (accessed May 14, 2020).
- ^ Mark Nudelman: Release 551 . June 11, 2019 (accessed May 15, 2020).
- ↑ Downloading less . (accessed on December 31, 2017).