diff --git a/c/todo.txt b/c/todo.txt
index 1b43398ba..40cd8613d 100644
--- a/c/todo.txt
+++ b/c/todo.txt
@@ -335,6 +335,7 @@ DOC:
 * 10-min
 * inverse-transform-sampling example at cookbook.
 * mlr -F and -K. Note -l -L -f -F -k -K.
+* section toggles
 * go/d/rust cmps @ getline
 * ruby/python cmps @ mand
 
diff --git a/doc/10-min.html b/doc/10-min.html
index 881c85cad..2c87b0867 100644
--- a/doc/10-min.html
+++ b/doc/10-min.html
@@ -193,7 +193,13 @@ Miller commands were run with pretty-print-tabular output format.
 </div>
 <p/>
 
+<p/>
+<button style="font-weight:bold;color:maroon;border:0" onclick="expand_all();" href="javascript:;">Expand all sections</button>
+<button style="font-weight:bold;color:maroon;border:0" onclick="collapse_all();" href="javascript:;">Collapse all sections</button>
+
 <a id="CSV-file_examples"/><h1>CSV-file examples</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_csv_file_examples');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_csv_file_examples" style="display: block">
 
 <p/><boldmaroon> Sample CSV data file: </boldmaroon>
 
@@ -524,7 +530,10 @@ square   purple 1              72.373500    72.373500     72.373500
 </div>
 <p/>
 
+</div>
 <a id="Choices_for_printing_to_files"/><h1>Choices for printing to files</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_printing_to_files');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_printing_to_files" style="display: block">
 
 <p/>Often we want to print output <boldmaroon>to the screen</boldmaroon>. Miller does this by default, as we&rsquo;ve
 seen in the previous examples.
@@ -652,7 +661,10 @@ purple,triangle,0,65,80.1405,5.8240
 <p/>
 </td></tr></table>
 
+</div>
 <a id="Other-format_examples"/><h1>Other-format examples</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_other_format_examples');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_other_format_examples" style="display: block">
 
 <p/>What&rsquo;s a CSV file, really? It&rsquo;s an array of rows, or
 <i>records</i>, each being a list of key-value pairs, or <i>fields</i>: for CSV
@@ -707,7 +719,10 @@ other format input data.</boldmaroon>  And you can read from one format, do any
 record-processing, and output to the same format as the input, or to a
 different output format.
 
+</div>
 <a id="SQL-output_examples"/><h1>SQL-output examples</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_sql_output_examples');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_sql_output_examples" style="display: block">
 
 <p/>I like to produce SQL-query output with header-column and tab delimiter:
 this is CSV but with a tab instead of a comma, also known as TSV. Then I
@@ -820,7 +835,10 @@ standard 10009872    108
 <p/>Again, all the examples in the CSV section apply here &mdash; just change the input-format
 flags.
 
+</div>
 <a id="Log-processing_examples"/><h1>Log-processing examples</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_log_processing_examples');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_log_processing_examples" style="display: block">
 
 <p/>Another of my favorite use-cases for Miller is doing ad-hoc processing of
 log-file data.  Here&rsquo;s where DKVP format really shines: one, since the
@@ -1038,11 +1056,16 @@ time                 batch_size num_filtered
 </div>
 <p/>
 
+</div>
 <a id="More"/><h1>More</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_more');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_more" style="display: block">
 
 <p/>Please see the <a href="reference.html">reference</a> for complete
 information, as well as the <a href="faq.html">FAQ</a> and the <a
 href="cookbook.html">cookbook</a> for more tips.
+
+</div>
     </div>
   </td>
 
diff --git a/doc/content-for-10-min.html b/doc/content-for-10-min.html
index bf9349058..1353bda51 100644
--- a/doc/content-for-10-min.html
+++ b/doc/content-for-10-min.html
@@ -1,6 +1,12 @@
 POKI_PUT_TOC_HERE
 
+<p/>
+<button style="font-weight:bold;color:maroon;border:0" onclick="expand_all();" href="javascript:;">Expand all sections</button>
+<button style="font-weight:bold;color:maroon;border:0" onclick="collapse_all();" href="javascript:;">Collapse all sections</button>
+
 <h1>CSV-file examples</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_csv_file_examples');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_csv_file_examples" style="display: block">
 
 <p/><boldmaroon> Sample CSV data file: </boldmaroon>
 
@@ -66,7 +72,10 @@ POKI_RUN_COMMAND{{mlr --icsv --oxtab --from example.csv stats1 -a p0,p10,p25,p50
 POKI_RUN_COMMAND{{mlr --icsv --opprint --from example.csv stats1 -a count,min,mean,max -f quantity -g shape}}HERE
 POKI_RUN_COMMAND{{mlr --icsv --opprint --from example.csv stats1 -a count,min,mean,max -f quantity -g shape,color}}HERE
 
+</div>
 <h1>Choices for printing to files</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_printing_to_files');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_printing_to_files" style="display: block">
 
 <p/>Often we want to print output <boldmaroon>to the screen</boldmaroon>. Miller does this by default, as we&rsquo;ve
 seen in the previous examples.
@@ -157,7 +166,10 @@ POKI_RUN_COMMAND{{cat square.csv}}HERE
 POKI_RUN_COMMAND{{cat triangle.csv}}HERE
 </td></tr></table>
 
+</div>
 <h1>Other-format examples</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_other_format_examples');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_other_format_examples" style="display: block">
 
 <p/>What&rsquo;s a CSV file, really? It&rsquo;s an array of rows, or
 <i>records</i>, each being a list of key-value pairs, or <i>fields</i>: for CSV
@@ -212,7 +224,10 @@ other format input data.</boldmaroon>  And you can read from one format, do any
 record-processing, and output to the same format as the input, or to a
 different output format.
 
+</div>
 <h1>SQL-output examples</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_sql_output_examples');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_sql_output_examples" style="display: block">
 
 <p/>I like to produce SQL-query output with header-column and tab delimiter:
 this is CSV but with a tab instead of a comma, also known as TSV. Then I
@@ -325,7 +340,10 @@ standard 10009872    108
 <p/>Again, all the examples in the CSV section apply here &mdash; just change the input-format
 flags.
 
+</div>
 <h1>Log-processing examples</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_log_processing_examples');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_log_processing_examples" style="display: block">
 
 <p/>Another of my favorite use-cases for Miller is doing ad-hoc processing of
 log-file data.  Here&rsquo;s where DKVP format really shines: one, since the
@@ -359,8 +377,13 @@ POKI_INCLUDE_AND_RUN_ESCAPED(10-2.sh)HERE
 POKI_RUN_COMMAND{{mlr --opprint group-like log.txt}}HERE
 POKI_RUN_COMMAND{{mlr --opprint group-like then sec2gmt time log.txt}}HERE
 
+</div>
 <h1>More</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_more');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_more" style="display: block">
 
 <p/>Please see the <a href="reference.html">reference</a> for complete
 information, as well as the <a href="faq.html">FAQ</a> and the <a
 href="cookbook.html">cookbook</a> for more tips.
+
+</div>
diff --git a/doc/content-for-cookbook.html b/doc/content-for-cookbook.html
index a4f0f3972..e1938f77d 100644
--- a/doc/content-for-cookbook.html
+++ b/doc/content-for-cookbook.html
@@ -1,11 +1,17 @@
 POKI_PUT_TOC_HERE
 
+<p/>
+<button style="font-weight:bold;color:maroon;border:0" onclick="expand_all();" href="javascript:;">Expand all sections</button>
+<button style="font-weight:bold;color:maroon;border:0" onclick="collapse_all();" href="javascript:;">Collapse all sections</button>
+
 <p/><b>Disclaimer:</b> This page is about how to do some corner-case things in
 ways you mightn&rsquo;t have thought of. For an intro, please also see
 <a href="10-min.html">Miller in 10 minutes</a>.
 
 <!-- ================================================================ -->
 <h1>Parsing log-file output</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_parsing_log_file_output');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_parsing_log_file_output" style="display: block">
 
 <p/>This, of course, depends highly on what&rsquo;s in your log files. But, as
 an example, suppose you have log-file lines such as
@@ -17,7 +23,10 @@ I prefer to pre-filter with <tt>grep</tt> and/or <tt>sed</tt> to extract the str
 POKI_CARDIFY(grep 'various sorts' *.log | sed 's/.*} //' | mlr --fs space --repifs --oxtab stats1 -a min,p10,p50,p90,max -f time -g status)HERE
 
 <!-- ================================================================ -->
+</div>
 <h1>Rectangularizing data</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_rectangularizing_data');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_rectangularizing_data" style="display: block">
 
 <p/>Suppose you have a method (in whatever language) which is printing things of the form
 
@@ -48,7 +57,10 @@ output when you see the inner IDs.
 POKI_INCLUDE_AND_RUN_ESCAPED(data/rect.sh)HERE
 
 <!-- ================================================================ -->
+</div>
 <h1>Bulk rename of field names</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_bulk_rename');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_bulk_rename" style="display: block">
 
 POKI_RUN_COMMAND{{cat data/spaces.csv}}HERE
 POKI_RUN_COMMAND{{mlr --csv rename -r -g ' ,_'  data/spaces.csv}}HERE
@@ -61,7 +73,10 @@ POKI_RUN_COMMAND{{cat data/bulk-rename-for-loop.mlr}}HERE
 POKI_RUN_COMMAND{{mlr --icsv --opprint put -f data/bulk-rename-for-loop.mlr data/spaces.csv}}HERE
 
 <!-- ================================================================ -->
+</div>
 <h1>Headerless CSV on input or output</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_headerless_csv');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_headerless_csv" style="display: block">
 
 <p/>Sometimes we get CSV files which lack a header. For example:
 
@@ -85,7 +100,10 @@ POKI_RUN_COMMAND{{head -5 data/colored-shapes.dkvp | mlr --ocsv cat}}HERE
 POKI_RUN_COMMAND{{head -5 data/colored-shapes.dkvp | mlr --ocsv --headerless-csv-output cat}}HERE
 
 <!-- ================================================================ -->
+</div>
 <h1>Regularizing ragged CSV</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_rectangularizing_ragged_csv');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_rectangularizing_ragged_csv" style="display: block">
 
 <p/>Miller handles compliant CSV: in particular, it&rsquo;s an error if the
 number of data fields in a given data line don&rsquo;t match the number of
@@ -102,7 +120,10 @@ or, more simply,
 POKI_INCLUDE_AND_RUN_ESCAPED(data/ragged-csv-2.sh)HERE
 
 <!-- ================================================================ -->
+</div>
 <h1>Program timing</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_program_timing');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_program_timing" style="display: block">
 
 This admittedly artificial example demonstrates using Miller time and stats
 functions to introspectly acquire some information about Miller&rsquo;s own
@@ -112,7 +133,10 @@ timestamps.
 POKI_INCLUDE_ESCAPED(data/timing-example.txt)HERE
 
 <!-- ================================================================ -->
+</div>
 <h1>Memoization with out-of-stream variables</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_memoization_with_oosvars');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_memoization_with_oosvars" style="display: block">
 
 <p/> The recursive function for the Fibonacci sequence is famous for its computational complexity.
 Namely, using
@@ -131,7 +155,10 @@ of previous computations:
 POKI_INCLUDE_AND_RUN_ESCAPED(data/fibo-cached.sh)HERE
 
 <!-- ================================================================ -->
+</div>
 <h1>Finding missing dates</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_finding_missing_dates');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_finding_missing_dates" style="display: block">
 
 <p/>Suppose you have some date-stamped data which may (or may not) be missing entries for one or more dates:
 
@@ -153,7 +180,10 @@ POKI_RUN_COMMAND{{mlr cat -n then filter '$n >= 770 && $n <= 780' data/miss-date
 POKI_RUN_COMMAND{{mlr cat -n then filter '$n >= 1115 && $n <= 1125' data/miss-date.csv}}HERE
 
 <!-- ================================================================ -->
+</div>
 <h1>Generating random variables</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_generating_random_variables');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_generating_random_variables" style="display: block">
 
 <p/>Here can chain together a few simple building blocks:
 
@@ -177,7 +207,10 @@ The output is as follows:
 POKI_RUN_COMMAND{{sh expo-sample.sh}}HERE
 
 <!-- ================================================================ -->
+</div>
 <h1>Two-pass algorithms</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_two_pass_algorithms');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_two_pass_algorithms" style="display: block">
 
 <p/>Miller is a streaming record processor; commands are performed once per
 record. This makes Miller particularly suitable for single-pass algorithms,
@@ -220,7 +253,10 @@ POKI_RUN_COMMAND{{cat data/maxrows.mlr}}HERE
 POKI_RUN_COMMAND{{mlr --itsv --opprint put -q -f data/maxrows.mlr data/maxrows.tsv}}HERE
 
 <!-- ================================================================ -->
+</div>
 <h1>Filtering paragraphs of text</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_filtering_paragraphs_of_text');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_filtering_paragraphs_of_text" style="display: block">
 
 <p/>The idea is to use a record separator which is a pair of newlines. Then, if
 you want each paragraph to be a record with a single value, use a
@@ -235,12 +271,18 @@ POKI_RUN_COMMAND{{mlr --from paragraphs.txt --nidx --rs '\n\n' --fs '\001' filte
 POKI_RUN_COMMAND{{mlr --from paragraphs.txt --nidx --rs '\n\n' --fs '\n' cut  -f 1,3}}HERE
 
 <!-- ================================================================ -->
+</div>
 <h1>Doing arithmetic on fields with currency symbols</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_doing_arithmetic_with_currency_symbols');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_doing_arithmetic_with_currency_symbols" style="display: block">
 
 POKI_INCLUDE_ESCAPED(data/dollar-sign.txt)HERE
 
 <!-- ================================================================ -->
+</div>
 <h1>Using out-of-stream variables</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_using_oosvars');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_using_oosvars" style="display: block">
 
 <p/> One of Miller&rsquo;s strengths is its compact notation: for example, given input of the form
 
@@ -322,3 +364,5 @@ POKI_RUN_COMMAND{{mlr --opprint put '$x_delta = is_present(@last[$a]) ? $x - @la
 POKI_INCLUDE_AND_RUN_ESCAPED(verb-example-ewma.sh)HERE
 
 POKI_INCLUDE_AND_RUN_ESCAPED(oosvar-example-ewma.sh)HERE
+
+</div>
diff --git a/doc/cookbook.html b/doc/cookbook.html
index c257865d5..87f3fa40f 100644
--- a/doc/cookbook.html
+++ b/doc/cookbook.html
@@ -211,12 +211,18 @@ Miller commands were run with pretty-print-tabular output format.
 </div>
 <p/>
 
+<p/>
+<button style="font-weight:bold;color:maroon;border:0" onclick="expand_all();" href="javascript:;">Expand all sections</button>
+<button style="font-weight:bold;color:maroon;border:0" onclick="collapse_all();" href="javascript:;">Collapse all sections</button>
+
 <p/><b>Disclaimer:</b> This page is about how to do some corner-case things in
 ways you mightn&rsquo;t have thought of. For an intro, please also see
 <a href="10-min.html">Miller in 10 minutes</a>.
 
 <!-- ================================================================ -->
 <a id="Parsing_log-file_output"/><h1>Parsing log-file output</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_parsing_log_file_output');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_parsing_log_file_output" style="display: block">
 
 <p/>This, of course, depends highly on what&rsquo;s in your log files. But, as
 an example, suppose you have log-file lines such as
@@ -240,7 +246,10 @@ grep 'various sorts' *.log | sed 's/.*} //' | mlr --fs space --repifs --oxtab st
 <p/>
 
 <!-- ================================================================ -->
+</div>
 <a id="Rectangularizing_data"/><h1>Rectangularizing data</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_rectangularizing_data');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_rectangularizing_data" style="display: block">
 
 <p/>Suppose you have a method (in whatever language) which is printing things of the form
 
@@ -347,7 +356,10 @@ outer=3,middle=31,inner1=313,inner2=314
 <p/>
 
 <!-- ================================================================ -->
+</div>
 <a id="Bulk_rename_of_field_names"/><h1>Bulk rename of field names</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_bulk_rename');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_bulk_rename" style="display: block">
 
 <p/>
 <div class="pokipanel">
@@ -413,7 +425,10 @@ def  a_b_c g_h_i
 <p/>
 
 <!-- ================================================================ -->
+</div>
 <a id="Headerless_CSV_on_input_or_output"/><h1>Headerless CSV on input or output</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_headerless_csv');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_headerless_csv" style="display: block">
 
 <p/>Sometimes we get CSV files which lack a header. For example:
 
@@ -514,7 +529,10 @@ purple,triangle,0,51,0.4355354501763202,0.8591292672156728,0.8122903963006748,5.
 <p/>
 
 <!-- ================================================================ -->
+</div>
 <a id="Regularizing_ragged_CSV"/><h1>Regularizing ragged CSV</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_rectangularizing_ragged_csv');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_rectangularizing_ragged_csv" style="display: block">
 
 <p/>Miller handles compliant CSV: in particular, it&rsquo;s an error if the
 number of data fields in a given data line don&rsquo;t match the number of
@@ -576,7 +594,10 @@ a,b,c
 <p/>
 
 <!-- ================================================================ -->
+</div>
 <a id="Program_timing"/><h1>Program timing</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_program_timing');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_program_timing" style="display: block">
 
 This admittedly artificial example demonstrates using Miller time and stats
 functions to introspectly acquire some information about Miller&rsquo;s own
@@ -618,7 +639,10 @@ t_delta_max  5.388259888e-05
 <p/>
 
 <!-- ================================================================ -->
+</div>
 <a id="Memoization_with_out-of-stream_variables"/><h1>Memoization with out-of-stream variables</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_memoization_with_oosvars');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_memoization_with_oosvars" style="display: block">
 
 <p/> The recursive function for the Fibonacci sequence is famous for its computational complexity.
 Namely, using
@@ -649,32 +673,32 @@ $ mlr --ofmt '%.9lf' --opprint seqgen --start 1 --stop 28 then put '
 i  o      fcount  seconds_delta
 1  1      1       0
 2  2      3       0.000031948
-3  3      5       0.000012159
-4  5      9       0.000015020
-5  8      15      0.000020981
-6  13     25      0.000027895
-7  21     41      0.000044107
-8  34     67      0.000065804
-9  55     109     0.000105143
-10 89     177     0.000167847
-11 144    287     0.000271082
-12 233    465     0.000427961
-13 377    753     0.000688076
-14 610    1219    0.001102924
-15 987    1973    0.001820087
-16 1597   3193    0.002871990
-17 2584   5167    0.004658937
-18 4181   8361    0.007560968
-19 6765   13529   0.012096167
-20 10946  21891   0.019388914
-21 17711  35421   0.031304121
-22 28657  57313   0.050275803
-23 46368  92735   0.080559015
-24 75025  150049  0.136618137
-25 121393 242785  0.208474874
-26 196418 392835  0.335786104
-27 317811 635621  0.553169966
-28 514229 1028457 0.884209871
+3  3      5       0.000013113
+4  5      9       0.000014782
+5  8      15      0.000022173
+6  13     25      0.000028849
+7  21     41      0.000045061
+8  34     67      0.000067949
+9  55     109     0.000108004
+10 89     177     0.000173092
+11 144    287     0.000277996
+12 233    465     0.000439882
+13 377    753     0.000705004
+14 610    1219    0.001131058
+15 987    1973    0.001841068
+16 1597   3193    0.003005981
+17 2584   5167    0.004643917
+18 4181   8361    0.007503033
+19 6765   13529   0.012021065
+20 10946  21891   0.019377947
+21 17711  35421   0.031213999
+22 28657  57313   0.050358057
+23 46368  92735   0.080504894
+24 75025  150049  0.131229162
+25 121393 242785  0.218618870
+26 196418 392835  0.372801065
+27 317811 635621  0.605077982
+28 514229 1028457 0.981553078
 </pre>
 </div>
 <p/>
@@ -706,39 +730,42 @@ $ mlr --ofmt '%.9lf' --opprint seqgen --start 1 --stop 28 then put '
 ' then put '$seconds=systime()' then step -a delta -f seconds then cut -x -f seconds
 i  o      fcount seconds_delta
 1  1      1      0
-2  2      3      0.000035048
+2  2      3      0.000036001
 3  3      3      0.000013113
-4  5      3      0.000010967
+4  5      3      0.000011921
 5  8      3      0.000010967
 6  13     3      0.000010014
-7  21     3      0.000010014
-8  34     3      0.000010014
-9  55     3      0.000011921
-10 89     3      0.000010014
-11 144    3      0.000010014
-12 233    3      0.000014067
-13 377    3      0.000010014
+7  21     3      0.000010967
+8  34     3      0.000010967
+9  55     3      0.000012159
+10 89     3      0.000009775
+11 144    3      0.000011206
+12 233    3      0.000013828
+13 377    3      0.000010967
 14 610    3      0.000010014
-15 987    3      0.000010014
-16 1597   3      0.000009775
-17 2584   3      0.000011206
-18 4181   3      0.000008821
-19 6765   3      0.000010014
-20 10946  3      0.000010014
+15 987    3      0.000011206
+16 1597   3      0.000010014
+17 2584   3      0.000009775
+18 4181   3      0.000010014
+19 6765   3      0.000011206
+20 10946  3      0.000009775
 21 17711  3      0.000010014
 22 28657  3      0.000010014
-23 46368  3      0.000011921
+23 46368  3      0.000013113
 24 75025  3      0.000010014
-25 121393 3      0.000011206
-26 196418 3      0.000009775
-27 317811 3      0.000010014
+25 121393 3      0.000010967
+26 196418 3      0.000010014
+27 317811 3      0.000010967
 28 514229 3      0.000010014
 </pre>
 </div>
 <p/>
 
 <!-- ================================================================ -->
+</div>
 <a id="Finding_missing_dates"/><h1>Finding missing dates</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_finding_missing_dates');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_finding_missing_dates" style="display: block">
 
 <p/>Suppose you have some date-stamped data which may (or may not) be missing entries for one or more dates:
 
@@ -849,7 +876,10 @@ n=1125,1=2015-04-05,2=182528
 <p/>
 
 <!-- ================================================================ -->
+</div>
 <a id="Generating_random_variables"/><h1>Generating random variables</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_generating_random_variables');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_generating_random_variables" style="display: block">
 
 <p/>Here can chain together a few simple building blocks:
 
@@ -963,7 +993,10 @@ bin_lo   bin_hi   u_count                        s_count
 <p/>
 
 <!-- ================================================================ -->
+</div>
 <a id="Two-pass_algorithms"/><h1>Two-pass algorithms</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_two_pass_algorithms');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_two_pass_algorithms" style="display: block">
 
 <p/>Miller is a streaming record processor; commands are performed once per
 record. This makes Miller particularly suitable for single-pass algorithms,
@@ -1131,7 +1164,10 @@ green  purple 5 0.203577
 <p/>
 
 <!-- ================================================================ -->
+</div>
 <a id="Filtering_paragraphs_of_text"/><h1>Filtering paragraphs of text</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_filtering_paragraphs_of_text');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_filtering_paragraphs_of_text" style="display: block">
 
 <p/>The idea is to use a record separator which is a pair of newlines. Then, if
 you want each paragraph to be a record with a single value, use a
@@ -1211,7 +1247,10 @@ falls mainly on the plain. The rain in Spain falls mainly on the plain. The
 <p/>
 
 <!-- ================================================================ -->
+</div>
 <a id="Doing_arithmetic_on_fields_with_currency_symbols"/><h1>Doing arithmetic on fields with currency symbols</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_doing_arithmetic_with_currency_symbols');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_doing_arithmetic_with_currency_symbols" style="display: block">
 
 <p/>
 <div class="pokipanel">
@@ -1253,7 +1292,10 @@ Amount_sum
 <p/>
 
 <!-- ================================================================ -->
+</div>
 <a id="Using_out-of-stream_variables"/><h1>Using out-of-stream variables</h1>
+<button style="font-weight:bold;color:maroon;border:0" padding=0 onclick="toggle_by_name('section_toggle_using_oosvars');" href="javascript:;">Toggle section visibility</button>
+<div id="section_toggle_using_oosvars" style="display: block">
 
 <p/> One of Miller&rsquo;s strengths is its compact notation: for example, given input of the form
 
@@ -1650,6 +1692,8 @@ wye pan 5 0.5732889198020006  0.8636244699032729  0.391064
 </pre>
 </div>
 <p/>
+
+</div>
     </div>
   </td>