… | |
… | |
63 | extensions. Some extensions can also be configured, for example, |
63 | extensions. Some extensions can also be configured, for example, |
64 | scrollback search mode is triggered by B<M-s>. You can move it to any |
64 | scrollback search mode is triggered by B<M-s>. You can move it to any |
65 | other combination either by setting the B<searchable-scrollback> resource: |
65 | other combination either by setting the B<searchable-scrollback> resource: |
66 | |
66 | |
67 | URxvt.searchable-scrollback: CM-s |
67 | URxvt.searchable-scrollback: CM-s |
|
|
68 | |
|
|
69 | =item Why doesn't rxvt-unicode read my resources? |
|
|
70 | |
|
|
71 | Well, why, indeed? It does, in a way very similar to other X |
|
|
72 | applications. Most importantly, this means that if you or your OS loads |
|
|
73 | resources into the X display (the right way to do it), rxvt-unicode will |
|
|
74 | ignore any resource files in your home directory. It will only read |
|
|
75 | F<$HOME/.Xdefaults> when no resources are attached to the display. |
|
|
76 | |
|
|
77 | If you have or use an F<$HOME/.Xresources> file, chances are that |
|
|
78 | resources are loaded into your X-server. In this case, you have to |
|
|
79 | re-login after every change (or run F<xrdb -merge $HOME/.Xresources>). |
|
|
80 | |
|
|
81 | Also consider the form resources have to use: |
|
|
82 | |
|
|
83 | URxvt.resource: value |
|
|
84 | |
|
|
85 | If you want to use another form (there are lots of different ways of |
|
|
86 | specifying resources), make sure you understand wether and why it |
|
|
87 | works. If unsure, use the form above. |
|
|
88 | |
|
|
89 | =item I can't get transparency working, what am I doing wrong? |
|
|
90 | |
|
|
91 | First of all, transparency isn't officially supported in rxvt-unicode, so |
|
|
92 | you are mostly on your own. Do not bug the author about it (but you may |
|
|
93 | bug everybody else). Also, if you can't get it working consider it a rite |
|
|
94 | of passage, and you failed. |
|
|
95 | |
|
|
96 | Here are three ways to get transparency. B<Do> read the manpage and option |
|
|
97 | descriptions for the programs mentioned and rxvt-unicode. Really, do it! |
|
|
98 | |
|
|
99 | 1. Use inheritPixmap: |
|
|
100 | |
|
|
101 | Esetroot wallpaper.jpg |
|
|
102 | @@RXVT_NAME@@ -ip -tint red -sh 40 |
|
|
103 | |
|
|
104 | That works. If you think it doesn't, you lack transparency and tinting |
|
|
105 | support, or you are unable to read. |
|
|
106 | |
|
|
107 | 2. Use a simple pixmap and emulate pseudo-transparency. This enables you |
|
|
108 | to use effects other than tinting and shading: Just shade/tint/whatever |
|
|
109 | your picture with gimp: |
|
|
110 | |
|
|
111 | convert wallpaper.jpg -blur 20x20 -modulate 30 background.xpm |
|
|
112 | @@RXVT_NAME@@ -pixmap background.xpm -pe automove-background |
|
|
113 | |
|
|
114 | That works. If you think it doesn't, you lack XPM and Perl support, or you |
|
|
115 | are unable to read. |
|
|
116 | |
|
|
117 | 3. Use an ARGB visual: |
|
|
118 | |
|
|
119 | @@RXVT_NAME@@ -depth 432 -fg grey90 -bg rgba:0000/0000/0000/c000 |
|
|
120 | |
|
|
121 | This requires XFT support, and support form your X-server. If that doesn't |
|
|
122 | work for you, blame Xorg and Keith Packard. ARGB visuals aren't there yet, |
|
|
123 | no matter what they claim. Rxvt-Unicode contains the neccessary bugfixes |
|
|
124 | and workarounds for Xft and Xlib to make it work. |
68 | |
125 | |
69 | =item Isn't rxvt supposed to be small? Don't all those features bloat? |
126 | =item Isn't rxvt supposed to be small? Don't all those features bloat? |
70 | |
127 | |
71 | I often get asked about this, and I think, no, they didn't cause extra |
128 | I often get asked about this, and I think, no, they didn't cause extra |
72 | bloat. If you compare a minimal rxvt and a minimal urxvt, you can see |
129 | bloat. If you compare a minimal rxvt and a minimal urxvt, you can see |
… | |
… | |
142 | No large bloated libraries (of course, none were linked in statically), |
199 | No large bloated libraries (of course, none were linked in statically), |
143 | except maybe libX11 :) |
200 | except maybe libX11 :) |
144 | |
201 | |
145 | =item Does it support tabs, can I have a tabbed rxvt-unicode? |
202 | =item Does it support tabs, can I have a tabbed rxvt-unicode? |
146 | |
203 | |
147 | rxvt-unicode does not directly support tabs. It will work fine with |
204 | Beginning with version 7.3, there is a perl extension that implements a |
148 | tabbing functionality of many window managers or similar tabbing programs, |
205 | simple tabbed terminal. It is installed by default, so any of these should |
149 | and its embedding-features allow it to be embedded into other programs, |
206 | give you tabs: |
150 | as witnessed by F<doc/rxvt-tabbed> or the upcoming C<Gtk2::URxvt> perl |
207 | |
151 | module, which features a tabbed urxvt (murxvt) terminal as an example |
208 | @@RXVT_NAME@@ -pe tabbed |
152 | embedding application. |
209 | |
|
|
210 | URxvt.perl-ext-common: default,tabbed |
|
|
211 | |
|
|
212 | It will also work fine with tabbing functionality of many window managers |
|
|
213 | or similar tabbing programs, and its embedding-features allow it to be |
|
|
214 | embedded into other programs, as witnessed by F<doc/rxvt-tabbed> or |
|
|
215 | the upcoming C<Gtk2::URxvt> perl module, which features a tabbed urxvt |
|
|
216 | (murxvt) terminal as an example embedding application. |
153 | |
217 | |
154 | =item How do I know which rxvt-unicode version I'm using? |
218 | =item How do I know which rxvt-unicode version I'm using? |
155 | |
219 | |
156 | The version number is displayed with the usage (-h). Also the escape |
220 | The version number is displayed with the usage (-h). Also the escape |
157 | sequence C<ESC [ 8 n> sets the window title to the version number. When |
221 | sequence C<ESC [ 8 n> sets the window title to the version number. When |
… | |
… | |
159 | daemon. |
223 | daemon. |
160 | |
224 | |
161 | =item I am using Debian GNU/Linux and have a problem... |
225 | =item I am using Debian GNU/Linux and have a problem... |
162 | |
226 | |
163 | The Debian GNU/Linux package of rxvt-unicode in sarge contains large |
227 | The Debian GNU/Linux package of rxvt-unicode in sarge contains large |
164 | patches that considerably change the behaviour of rxvt-unicode. Before |
228 | patches that considerably change the behaviour of rxvt-unicode (but |
165 | reporting a bug to the original rxvt-unicode author please download and |
229 | unfortunately this notice has been removed). Before reporting a bug to |
166 | install the genuine version (L<http://software.schmorp.de#rxvt-unicode>) |
230 | the original rxvt-unicode author please download and install the genuine |
167 | and try to reproduce the problem. If you cannot, chances are that the |
231 | version (L<http://software.schmorp.de#rxvt-unicode>) and try to reproduce |
168 | problems are specific to Debian GNU/Linux, in which case it should be |
232 | the problem. If you cannot, chances are that the problems are specific to |
169 | reported via the Debian Bug Tracking System (use C<reportbug> to report |
233 | Debian GNU/Linux, in which case it should be reported via the Debian Bug |
170 | the bug). |
234 | Tracking System (use C<reportbug> to report the bug). |
171 | |
235 | |
172 | For other problems that also affect the Debian package, you can and |
236 | For other problems that also affect the Debian package, you can and |
173 | probably should use the Debian BTS, too, because, after all, it's also a |
237 | probably should use the Debian BTS, too, because, after all, it's also a |
174 | bug in the Debian version and it serves as a reminder for other users that |
238 | bug in the Debian version and it serves as a reminder for other users that |
175 | might encounter the same issue. |
239 | might encounter the same issue. |
176 | |
240 | |
177 | =item I am maintaining rxvt-unicode for distribution/OS XXX, any recommendation? |
241 | =item I am maintaining rxvt-unicode for distribution/OS XXX, any |
|
|
242 | recommendation? |
178 | |
243 | |
179 | You should build one binary with the default options. F<configure> |
244 | You should build one binary with the default options. F<configure> |
180 | now enables most useful options, and the trend goes to making them |
245 | now enables most useful options, and the trend goes to making them |
181 | runtime-switchable, too, so there is usually no drawback to enbaling them, |
246 | runtime-switchable, too, so there is usually no drawback to enbaling them, |
182 | except higher disk and possibly memory usage. The perl interpreter should |
247 | except higher disk and possibly memory usage. The perl interpreter should |
… | |
… | |
194 | C<--enable-everything> (less useful, it will be very big due to a lot of |
259 | C<--enable-everything> (less useful, it will be very big due to a lot of |
195 | encodings built-in that increase download times and are rarely used). |
260 | encodings built-in that increase download times and are rarely used). |
196 | |
261 | |
197 | =item I need to make it setuid/setgid to support utmp/ptys on my OS, is this safe? |
262 | =item I need to make it setuid/setgid to support utmp/ptys on my OS, is this safe? |
198 | |
263 | |
199 | Likely not. While I honestly try to make it secure, and am probably not |
264 | It should be, starting with release 7.1. You are encouraged to properly |
200 | bad at it, I think it is simply unreasonable to expect all of freetype |
265 | install urxvt with privileges necessary for your OS now. |
201 | + fontconfig + xft + xlib + perl + ... + rxvt-unicode itself to all be |
|
|
202 | secure. Also, rxvt-unicode disables some options when it detects that it |
|
|
203 | runs setuid or setgid, which is not nice. Besides, with the embedded perl |
|
|
204 | interpreter the possibility for security problems easily multiplies. |
|
|
205 | |
266 | |
206 | Elevated privileges are only required for utmp and pty operations on some |
267 | When rxvt-unicode detects that it runs setuid or setgid, it will fork |
207 | systems (for example, GNU/Linux doesn't need any extra privileges for |
268 | into a helper process for privileged operations (pty handling on some |
208 | ptys, but some need it for utmp support). It is planned to mvoe this into |
269 | systems, utmp/wtmp/lastlog handling on others) and drop privileges |
209 | a forked handler process, but this is not yet done. |
270 | immediately. This is much safer than most other terminals that keep |
|
|
271 | privileges while running (but is more relevant to urxvt, as it contains |
|
|
272 | things as perl interpreters, which might be "helpful" to attackers). |
210 | |
273 | |
211 | So, while setuid/setgid operation is supported and not a problem on your |
274 | This forking is done as the very first within main(), which is very early |
212 | typical single-user-no-other-logins unix desktop, always remember that |
275 | and reduces possible bugs to initialisation code run before main(), or |
213 | its an awful lot of code, most of which isn't checked for security issues |
276 | things like the dynamic loader of your system, which should result in very |
214 | regularly. |
277 | little risk. |
215 | |
278 | |
216 | =item When I log-in to another system it tells me about missing terminfo data? |
279 | =item When I log-in to another system it tells me about missing terminfo data? |
217 | |
280 | |
218 | The terminal description used by rxvt-unicode is not as widely available |
281 | The terminal description used by rxvt-unicode is not as widely available |
219 | as that for xterm, or even rxvt (for which the same problem often arises). |
282 | as that for xterm, or even rxvt (for which the same problem often arises). |
… | |
… | |
1669 | B<< C<Ps = 12> >> Change colour of text cursor foreground to B<< C<Pt> >> |
1732 | B<< C<Ps = 12> >> Change colour of text cursor foreground to B<< C<Pt> >> |
1670 | B<< C<Ps = 13> >> Change colour of mouse foreground to B<< C<Pt> >> |
1733 | B<< C<Ps = 13> >> Change colour of mouse foreground to B<< C<Pt> >> |
1671 | B<< C<Ps = 17> >> Change colour of highlight characters to B<< C<Pt> >> |
1734 | B<< C<Ps = 17> >> Change colour of highlight characters to B<< C<Pt> >> |
1672 | B<< C<Ps = 18> >> Change colour of bold characters to B<< C<Pt> >> [deprecated, see 706] |
1735 | B<< C<Ps = 18> >> Change colour of bold characters to B<< C<Pt> >> [deprecated, see 706] |
1673 | B<< C<Ps = 19> >> Change colour of underlined characters to B<< C<Pt> >> [deprecated, see 707] |
1736 | B<< C<Ps = 19> >> Change colour of underlined characters to B<< C<Pt> >> [deprecated, see 707] |
1674 | B<< C<Ps = 20> >> Change default background to B<< C<Pt> >> |
1737 | B<< C<Ps = 20> >> Change background pixmap parameters (see section XPM) (Compile XPM). |
1675 | B<< C<Ps = 39> >> Change default foreground colour to B<< C<Pt> >>. |
1738 | B<< C<Ps = 39> >> Change default foreground colour to B<< C<Pt> >>. |
1676 | B<< C<Ps = 46> >> Change Log File to B<< C<Pt> >> I<unimplemented> |
1739 | B<< C<Ps = 46> >> Change Log File to B<< C<Pt> >> I<unimplemented> |
1677 | B<< C<Ps = 49> >> Change default background colour to B<< C<Pt> >>. |
1740 | B<< C<Ps = 49> >> Change default background colour to B<< C<Pt> >>. |
1678 | B<< C<Ps = 50> >> Set fontset to B<< C<Pt> >>, with the following special values of B<< C<Pt> >> (B<rxvt>) B<< C<#+n> >> change up B<< C<n> >> B<< C<#-n> >> change down B<< C<n> >> if B<< C<n> >> is missing of 0, a value of 1 is used I<empty> change to font0 B<< C<n> >> change to font B<< C<n> >> |
1741 | B<< C<Ps = 50> >> Set fontset to B<< C<Pt> >>, with the following special values of B<< C<Pt> >> (B<rxvt>) B<< C<#+n> >> change up B<< C<n> >> B<< C<#-n> >> change down B<< C<n> >> if B<< C<n> >> is missing of 0, a value of 1 is used I<empty> change to font0 B<< C<n> >> change to font B<< C<n> >> |
1679 | B<< C<Ps = 55> >> Log all scrollback buffer and all of screen to B<< C<Pt> >> |
1742 | B<< C<Ps = 55> >> Log all scrollback buffer and all of screen to B<< C<Pt> >> |
1680 | B<< C<Ps = 701> >> Change current locale to B<< C<Pt> >>, or, if B<< C<Pt> >> is B<< C<?> >>, return the current locale (Compile frills). |
1743 | B<< C<Ps = 701> >> Change current locale to B<< C<Pt> >>, or, if B<< C<Pt> >> is B<< C<?> >>, return the current locale (Compile frills). |
|
|
1744 | B<< C<Ps = 702> >> Request version if B<< C<Pt> >> is B<< C<?> >>, returning C<rxvt-unicode>, the resource name, the major and minor version numbers, e.g. C<ESC ] 702 ; rxvt-unicode ; urxvt ; 7 ; 4 ST>. |
1681 | B<< C<Ps = 704> >> Change colour of italic characters to B<< C<Pt> >> |
1745 | B<< C<Ps = 704> >> Change colour of italic characters to B<< C<Pt> >> |
1682 | B<< C<Ps = 705> >> Change background pixmap tint colour to B<< C<Pt> >> (Compile transparency). |
1746 | B<< C<Ps = 705> >> Change background pixmap tint colour to B<< C<Pt> >> (Compile transparency). |
1683 | B<< C<Ps = 706> >> Change colour of bold characters to B<< C<Pt> >> |
1747 | B<< C<Ps = 706> >> Change colour of bold characters to B<< C<Pt> >> |
1684 | B<< C<Ps = 707> >> Change colour of underlined characters to B<< C<Pt> >> |
1748 | B<< C<Ps = 707> >> Change colour of underlined characters to B<< C<Pt> >> |
1685 | B<< C<Ps = 710> >> Set normal fontset to B<< C<Pt> >>. Same as C<Ps = 50>. |
1749 | B<< C<Ps = 710> >> Set normal fontset to B<< C<Pt> >>. Same as C<Ps = 50>. |
… | |
… | |
1948 | alternative input methods (e.g. kinput2) and will also correctly |
2012 | alternative input methods (e.g. kinput2) and will also correctly |
1949 | set up the input for people using dead keys or compose keys. |
2013 | set up the input for people using dead keys or compose keys. |
1950 | |
2014 | |
1951 | =item --enable-unicode3 (default: off) |
2015 | =item --enable-unicode3 (default: off) |
1952 | |
2016 | |
|
|
2017 | Recommended to stay off unless you really need non-BMP characters. |
|
|
2018 | |
1953 | Enable direct support for displaying unicode codepoints above |
2019 | Enable direct support for displaying unicode codepoints above |
1954 | 65535 (the basic multilingual page). This increases storage |
2020 | 65535 (the basic multilingual page). This increases storage |
1955 | requirements per character from 2 to 4 bytes. X11 fonts do not yet |
2021 | requirements per character from 2 to 4 bytes. X11 fonts do not yet |
1956 | support these extra characters, but Xft does. |
2022 | support these extra characters, but Xft does. |
1957 | |
2023 | |
… | |
… | |
1967 | composite characters. This is required for proper viewing of text |
2033 | composite characters. This is required for proper viewing of text |
1968 | where accents are encoded as seperate unicode characters. This is |
2034 | where accents are encoded as seperate unicode characters. This is |
1969 | done by using precomposited characters when available or creating |
2035 | done by using precomposited characters when available or creating |
1970 | new pseudo-characters when no precomposed form exists. |
2036 | new pseudo-characters when no precomposed form exists. |
1971 | |
2037 | |
1972 | Without --enable-unicode3, the number of additional precomposed characters |
2038 | Without --enable-unicode3, the number of additional precomposed |
1973 | is rather limited (2048, if this is full, rxvt-unicode will use the |
2039 | characters is somewhat limited (the 6400 private use characters will be |
1974 | private use area, extending the number of combinations to 8448). With |
|
|
1975 | --enable-unicode3, no practical limit exists. |
2040 | (ab-)used). With --enable-unicode3, no practical limit exists. |
1976 | |
2041 | |
1977 | This option will also enable storage (but not display) of characters |
2042 | This option will also enable storage (but not display) of characters |
1978 | beyond plane 0 (>65535) when --enable-unicode3 was not specified. |
2043 | beyond plane 0 (>65535) when --enable-unicode3 was not specified. |
1979 | |
2044 | |
1980 | The combining table also contains entries for arabic presentation forms, |
2045 | The combining table also contains entries for arabic presentation forms, |
1981 | but these are not currently used. Bug me if you want these to be used (and |
2046 | but these are not currently used. Bug me if you want these to be used (and |
1982 | tell me how these are to be used...). |
2047 | tell me how these are to be used...). |
1983 | |
2048 | |
1984 | =item --enable-fallback(=CLASS) (default: Rxvt) |
2049 | =item --enable-fallback(=CLASS) (default: Rxvt) |
1985 | |
2050 | |
1986 | When reading resource settings, also read settings for class CLASS. To disable resource fallback use --disable-fallback. |
2051 | When reading resource settings, also read settings for class CLASS. To |
|
|
2052 | disable resource fallback use --disable-fallback. |
1987 | |
2053 | |
1988 | =item --with-res-name=NAME (default: urxvt) |
2054 | =item --with-res-name=NAME (default: urxvt) |
1989 | |
2055 | |
1990 | Use the given name as default application name when |
2056 | Use the given name as default application name when |
1991 | reading resources. Specify --with-res-name=rxvt to replace rxvt. |
2057 | reading resources. Specify --with-res-name=rxvt to replace rxvt. |
… | |
… | |
2045 | =item --enable-plain-scroll (default: on) |
2111 | =item --enable-plain-scroll (default: on) |
2046 | |
2112 | |
2047 | Add support for a very unobtrusive, plain-looking scrollbar that |
2113 | Add support for a very unobtrusive, plain-looking scrollbar that |
2048 | is the favourite of the rxvt-unicode author, having used it for |
2114 | is the favourite of the rxvt-unicode author, having used it for |
2049 | many years. |
2115 | many years. |
2050 | |
|
|
2051 | =item --enable-half-shadow (default: off) |
|
|
2052 | |
|
|
2053 | Make shadows on the scrollbar only half the normal width & height. |
|
|
2054 | only applicable to rxvt scrollbars. |
|
|
2055 | |
2116 | |
2056 | =item --enable-ttygid (default: off) |
2117 | =item --enable-ttygid (default: off) |
2057 | |
2118 | |
2058 | Change tty device setting to group "tty" - only use this if |
2119 | Change tty device setting to group "tty" - only use this if |
2059 | your system uses this type of security. |
2120 | your system uses this type of security. |
… | |
… | |
2086 | |
2147 | |
2087 | MWM-hints |
2148 | MWM-hints |
2088 | EWMH-hints (pid, utf8 names) and protocols (ping) |
2149 | EWMH-hints (pid, utf8 names) and protocols (ping) |
2089 | seperate underline colour (-underlineColor) |
2150 | seperate underline colour (-underlineColor) |
2090 | settable border widths and borderless switch (-w, -b, -bl) |
2151 | settable border widths and borderless switch (-w, -b, -bl) |
|
|
2152 | visual depth selection (-depth) |
2091 | settable extra linespacing /-lsp) |
2153 | settable extra linespacing /-lsp) |
2092 | iso-14755-2 and -3, and visual feedback |
2154 | iso-14755-2 and -3, and visual feedback |
2093 | backindex and forwardindex escape sequence |
|
|
2094 | window op and some xterm/OSC escape sequences |
|
|
2095 | tripleclickwords (-tcw) |
2155 | tripleclickwords (-tcw) |
2096 | settable insecure mode (-insecure) |
2156 | settable insecure mode (-insecure) |
2097 | keysym remapping support |
2157 | keysym remapping support |
2098 | cursor blinking and underline cursor (-cb, -uc) |
2158 | cursor blinking and underline cursor (-cb, -uc) |
2099 | XEmbed support (-embed) |
2159 | XEmbed support (-embed) |
2100 | user-pty (-pty-fd) |
2160 | user-pty (-pty-fd) |
2101 | hold on exit (-hold) |
2161 | hold on exit (-hold) |
2102 | skip builtin block graphics (-sbg) |
2162 | skip builtin block graphics (-sbg) |
|
|
2163 | |
|
|
2164 | It also enabled some non-essential features otherwise disabled, such as: |
|
|
2165 | |
|
|
2166 | some round-trip time optimisations |
|
|
2167 | nearest color allocation on pseudocolor screens |
|
|
2168 | UTF8_STRING supporr for selection |
2103 | sgr modes 90..97 and 100..107 |
2169 | sgr modes 90..97 and 100..107 |
|
|
2170 | backindex and forwardindex escape sequences |
|
|
2171 | view change/zero scorllback esacpe sequences |
|
|
2172 | locale switching escape sequence |
|
|
2173 | window op and some xterm/OSC escape sequences |
|
|
2174 | rectangular selections |
|
|
2175 | trailing space removal for selections |
|
|
2176 | verbose X error handling |
2104 | |
2177 | |
2105 | =item --enable-iso14755 (default: on) |
2178 | =item --enable-iso14755 (default: on) |
2106 | |
2179 | |
2107 | Enable extended ISO 14755 support (see @@RXVT_NAME@@(1), or |
2180 | Enable extended ISO 14755 support (see @@RXVT_NAME@@(1), or |
2108 | F<doc/rxvt.1.txt>). Basic support (section 5.1) is enabled by |
2181 | F<doc/rxvt.1.txt>). Basic support (section 5.1) is enabled by |
… | |
… | |
2151 | |
2224 | |
2152 | =item --enable-pointer-blank (default: on) |
2225 | =item --enable-pointer-blank (default: on) |
2153 | |
2226 | |
2154 | Add support to have the pointer disappear when typing or inactive. |
2227 | Add support to have the pointer disappear when typing or inactive. |
2155 | |
2228 | |
2156 | =item --enable-perl (default: off) |
2229 | =item --enable-perl (default: on) |
2157 | |
2230 | |
2158 | Enable an embedded perl interpreter. See the B<@@RXVT_NAME@@perl(3)> |
2231 | Enable an embedded perl interpreter. See the B<@@RXVT_NAME@@perl(3)> |
2159 | manpage (F<doc/rxvtperl.txt>) for more info on this feature, or the files |
2232 | manpage (F<doc/rxvtperl.txt>) for more info on this feature, or the files |
2160 | in F<src/perl-ext/> for the extensions that are installed by default. The |
2233 | in F<src/perl-ext/> for the extensions that are installed by default. The |
2161 | perl interpreter that is used can be specified via the C<PERL> environment |
2234 | perl interpreter that is used can be specified via the C<PERL> environment |