Docstrings updated

docs/src/advanced.md

@@ -1,12 +1,6 @@
 # Advanced techniques
 
-Here we will show a few advanced techniques for data visualization using **Gnuplot.jl**.  The new concepts introduced in the examples are as follows:
-
-- a name can be associated to a dataset, in order to use it multiple times in a plot while sending it only once to gnuplot. A dataset name must begin with a `$`;
-
-- gnuplot is able to generate multiplot, i.e. a single figure containing multiple plots.  Each plot is identified by a numeric ID, starting from 1;
-
-- **Gnuplot.jl** is able to handle multiple sessions, i.e. multiple gnuplot processes running simultaneously.  Each session is identified by a symbol.  If the session ID is not specified the `:default` session is considered.
+Here we will show a few advanced techniques for data visualization using **Gnuplot.jl**.
 
 
 ```@setup abc
@@ -20,12 +14,14 @@ Gnuplot.exec("set term unknown")
 
 
 ## Named datasets
-A named dataset can be used multiple times in a plot, avoiding sending to gnuplot the same data multiple times.  A dataset name must always start with a `$`, and the dataset is defined as a `Pair{String, Tuple}`, e.g.:
+
+A dataset may have an associated name whose purpose is to use it multiple times for plotting, while sending it only once to gnuplot. A dataset name must begin with a `$`.
+
+A named dataset is defined as a `Pair{String, Tuple}`, e.g.:
 ```julia
 "\$name" => (1:10,)
 ```
-
-A named dataset can be used as an argument to both `@gp` and `gsp`, e.g.:
+and can be used as an argument to both `@gp` and `gsp`, e.g.:
 ```@example abc
 x = range(-2pi, stop=2pi, length=100);
 y = sin.(x)
@@ -107,6 +103,33 @@ saveas("ex012") # hide
 
 
 ## Multiple sessions
+
+**Gnuplot.jl** can handle multiple sessions, i.e. multiple gnuplot processes running simultaneously.  Each session is identified by a symbol.
+
+In order to redirect commands to a specific session simply insert a symbol into your `@gp` or `@gsp` call, e.g.:
+```@example abc
+@gp :GP1 "plot sin(x)"    # opens first window
+@gp :GP2 "plot sin(x)"    # opens secondo window
+@gp :- :GP1 "plot cos(x)" # add a plot on first window
+```
+If the session ID is not specified the `:default` session is considered.
+
+The names of all current sessions can be retrieved with [`session_names()`](@ref):
+```@repl abc
+println(session_names())
+```
+
+To quit a specific session use [`Gnuplot.quit()`](@ref):
+```@repl abc
+Gnuplot.quit(:GP1)
+```
+The output value is the exit status of the underlying gnuplot process.
+
+You may also quit all active sessions at once with [`Gnuplot.quitall()`](@ref):
+```@repl abc
+Gnuplot.quitall()
+```
+
 ## Histograms (1D)
 ## Histograms (2D)
 ## Contour lines

docs/src/basic.md

@@ -154,18 +154,18 @@ If the orientation is not the correct one you may adjust it with the gnuplot `ro
 using TestImages
 img = testimage("lighthouse");
 @gp "set size square" "set autoscale fix" img "rotate=-90deg with rgbimage notit"
-save(term="jpeg size 480,360", output="assets/ex007b.jpg") # hide
+saveas("ex007b") # hide
 ```
-![](assets/ex007b.jpg)
+![](assets/ex007b.png)
 
 
 To display a gray image use `with image` in place of `with rgbimage`, e.g.:
 ```@example abc
 img = testimage("walkbridge");
 @gp palette(:lapaz) "set size square" "set autoscale fix" img "rotate=-0.5pi with image notit"
-save(term="jpeg size 480,360", output="assets/ex007c.jpg") # hide
+saveas("ex007c") # hide
 ```
-![](assets/ex007c.jpg)
+![](assets/ex007c.png)
 
 Note that we used a custom palette (`:lapaz`, see [Palettes and line types](@ref)) and the rotation angle has been expressed in radians (`-0.5pi`).
 
@@ -184,19 +184,21 @@ saveas("ex008") # hide
 
 Note that the fourth array in the dataset, `x./20`, is used as by gnuplot as point size (`ps var`).  Also note that all the keywords discussed above can also be used in 3D plots.
 
+
 ## Palettes and line types
 The **Gnuplot.jl** package comes with all the [ColorSchemes](https://juliagraphics.github.io/ColorSchemes.jl/stable/basics/#Pre-defined-schemes-1) palettes readily available.
 
-A gnuplot-compliant palette can be retrieved with `palette()`, and used as any other command.  The previous example may use an alternative palette with:
+A gnuplot-compliant palette can be retrieved with [`palette()`](@ref), and used as any other command.  The previous example may use an alternative palette with:
 ```@example abc
 x = 0:0.1:10pi
-@gsp palette(:viridis) cbr=[-1,1].*30  x  sin.(x) .* x  cos.(x) .* x  x./20  "w p pt 7 ps var lc pal"
+@gsp palette(:viridis) cbr=[-1,1].*30 :-
+@gsp :-  x  sin.(x) .* x  cos.(x) .* x  x./20  "w p pt 7 ps var lc pal"
 saveas("ex008a") # hide
 ```
 ![](assets/ex008a.png)
 
 
-The [ColorSchemes](https://juliagraphics.github.io/ColorSchemes.jl/stable/basics/#Pre-defined-schemes-1) palettes can also be used to generate line types (actually just line colors), by means of the `linetypes()` function, e.g.
+The [ColorSchemes](https://juliagraphics.github.io/ColorSchemes.jl/stable/basics/#Pre-defined-schemes-1) palettes can also be used to generate line types (actually just line colors), by means of the [`linetypes()`](@ref) function, e.g.
 ```@example abc
 @gp linetypes(:deepsea)
 x = 1:0.1:4pi
@@ -207,12 +209,15 @@ saveas("ex009") # hide
 ```
 ![](assets/ex009.png)
 
-
+The list of all available palette can be retrieved with [`palette_names()`](@ref):
+```@repl abc
+palette_names()
+```
 
 
 ## Exporting plots to files
 
-The `save()` function allows to export all plots (as well as multiplots, see [Multiplot](@ref)) to a file using one of the many available gnuplot terminals.  To check which terminals are available in your platform type `set term` in your gnuplot terminal.
+The [`save()`](@ref) function allows to export all plots (as well as multiplots, see [Multiplot](@ref)) to a file using one of the many available gnuplot terminals.  To check which terminals are available in your platform type `set term` in your gnuplot terminal.
 
 All plots in this page have been saved with:
 ```julia