Manipulating Variables

f78 Manipulating Variables

Manipulating Variables

GNU info contains several variables whose values are looked at by various info commands. You can change the values of these variables, and thus change the behavior of info to more closely match your environment and info file reading manner.

M-x set-variable

Reads the name of a variable, and the value for it, in the echo area and then sets the variable to that value. Completion is available when reading the variable name; often, completion is available when reading the value to give to the variable, but that depends on the variable itself. If a variable does not supply multiple choices to complete over, it expects a numeric value.

M-x describe-variable

Reads the name of a variable in the echo area and then displays a brief description of what the variable affects.

What follows is a list of the variables that you can set in info.

automatic-footnotes

When set to On, footnotes appear and disappear automatically. This variable is On by default. When a node is selected, a window containing the footnotes which appear in that node is created, and the footnotes are displayed within the new window. The window that info creates to contain the footnotes is called ‘*Footnotes*’. If a node is selected which contains no footnotes, and a ‘*Footnotes*’ window is on the screen, the ‘*Footnotes*’ window is deleted. Footnote windows created in this fashion are not automatically tiled so that they can use as little of the display as is possible.

automatic-tiling

When set to On, creating or deleting a window resizes other windows. This variable is Off by default. Normally, typing ‘Ctrl-x, 2’ divides the current window into two equal parts. When automatic-tiling is set to On, all of the windows are resized automatically, keeping an equal number of lines visible in each window. There are exceptions to the automatic tiling; specifically, the windows ‘*Completions*’ and ‘*Footnotes*’ are not resized through automatic tiling; they remain their original size.

visible-bell

When set to On, GNU info attempts to flash the screen instead of ringing the bell. This variable is Off by default.

Of course, info can only flash the screen if the terminal allows it; in the case that the terminal does not allow it, the setting of this variable has no effect.

However, you can set the errors-ring-bell variable to Off to make Info perform quietly.

errors-ring-bell

When set to On, errors cause the bell to ring. The default setting of this variable is On.

gc-compressed-files

When set to On, info< ffb FONT SIZE=+1> garbage collects files which had to be uncompressed. The default value of this variable is Off. Whenever a node is visited in info, the info file containing that node is read into core, and info reads information about the tags and nodes contained in that file. Once the tags information is read by info, it is never forgotten. However, the actual text of the nodes does not need to remain in core unless a particular info window needs it. For non-compressed files, the text of the nodes does not remain in core when it is no longer in use. But decompressing a file can be a time consuming operation, and so info tries hard not to do it twice. gc-compressed-files tells info it is okay to garbage collect the text of the nodes of a file which was compressed on disk.

show-index-match

When set to On, the portion of the matched search string is highlighted in the message which explains where the matched search string was found. The default value of this variable is On. When info displays the location where an index match was found, (see next-index-match in Searching an info file), the portion of the string that you had typed is highlighted by displaying it in the inverse case from its surrounding characters.

scroll-behaviour

Controls what happens when forward scrolling is requested at the end of a node, or when backward scrolling is requested at the beginning of a node. The default value for this variable is Continuous. There are three possible values for this variable:

Continuous

Tries to get the first item in this node’s menu, or failing that, the ‘Next’ node, or failing that, the ‘Next’ of the ‘Up’. This behavior is identical to using the ‘]’ (global-next-node) and ‘[’ (global-prev- node) commands.

Next Only

Only tries to get the ‘Next’ node.

Page Only

Simply gives up, changing nothing. If scroll-behaviour is Page Only, no scrolling command can change the node that is being viewed.

scroll-step

The number of lines to scroll when the cursor moves out of the window. Scrolling happens automatically if the cursor has moved out of the visible portion of the node text when it is time to display. Usually the scrolling is done so as to put the cursor on the center line of the current window. However, if the variable scroll-step has a nonzero value, info attempts to scroll the node text by that many lines; if that is enough to bring the cursor back into the window, that is what is done. The default value of this variable is 0, thus placing the cursor (and the text it is attached to) in the center of the window. Setting this variable to 1 causes a kind of smooth scrolling which some people prefer.

ISO-Latin

When set to On, info accepts and displays ISO Latin characters. By default, Info assumes an ASCII character set. ISO-Latin 20f tells info that it is running in an environment where the European standard character set is in use, and allows you to input such characters to info, as well as display them.