parallel_cheat.fodt: Initial cheat sheet.

doc/release_new_version

@@ -207,7 +207,7 @@ from:tange@gnu.org
 to:parallel@gnu.org, bug-parallel@gnu.org
 stable-bcc: Jesse Alama <jessealama@fastmail.fm>
 
-Subject: GNU Parallel 20190222 ('INF/Al-Baghuz Fawqani') released <<[stable]>>
+Subject: GNU Parallel 20190222 ('indien pakistan Kashmir') released <<[stable]>>
 
 GNU Parallel 20190222 ('') <<[stable]>> has been released. It is available for download at: http://ftpmirror.gnu.org/parallel/
 
@@ -220,29 +220,9 @@ Quote of the month:
 
 New in this release:
 
-* --shard makes it possible to send input to a the same jobslot based on the value in one column of the input. It is similar to sharding in databases.
+https://calendar.colorado.edu/event/high_throughput_computing_on_rmacc_summit_and_beyond#.XH2NBhB7mV4
 
-* --shellquote --shellquote will shell quote the input twice.
+https://www.cheatography.com/cpriest/cheat-sheets/gnu-parallel/
-
-* GNU Parallel is available in Termux https://github.com/termux/termux-packages/tree/master/packages/parallel
-
-* Linux, command line & MetaCentrum https://trapa.cz/sites/default/files/linux_bash_metacentrum_course_4.pdf
-
-* How to supercharge your bash workflows with GNU parallel https://medium.freecodecamp.org/how-to-supercharge-your-bash-workflows-with-gnu-parallel-53aab0aea141
-
-* GNU Parallel Spring 2017 https://www.youtube.com/watch?v=LHb29uW_KyI
-
-* Parallelizing Freesurfer blog.cogneurostats.com/?p=148
-
-* FreeSurfer #4: Running recon-all in Parallel https://www.youtube.com/watch?v=XHN2tm3tNaw
-
-* FreeSurfer: recon-all https://www.neurotrivial.com/2019/01/24/freesurfer-recon-all/
-
-* Come ridimensionare 10k foto con la riga di comando https://pigrecoinfinito.wordpress.com/2018/12/22/come-ridimensionare-10k-foto-con-la-riga-di-comando/
-
-* 并行处理 – Gnu Parallel：嵌套并行 https://codeday.me/bug/20190122/552902.html
-
-* シェルスクリプトでコマンドを並列実行する方法https://www.kwbtblog.com/entry/2019/01/12/020423
 
 * Bug fixes and man page updates.
 

src/Makefile.am

@@ -22,7 +22,8 @@ doc_DATA = parallel.html env_parallel.html sem.html sql.html		\
 	parset.texi \
 	parallel.pdf env_parallel.pdf sem.pdf sql.pdf niceload.pdf	\
 	parallel_tutorial.pdf parallel_book.pdf parallel_design.pdf	\
-	parallel_alternatives.pdf parcat.pdf parset.pdf
+	parallel_alternatives.pdf parcat.pdf parset.pdf			\
+	parallel_cheat.pdf
 endif
 
 # Build documentation file if the tool to build exists.
@@ -257,6 +258,10 @@ parset.pdf: parset.pod
 	pod2pdf --output-file $(srcdir)/parset.pdf $(srcdir)/parset.pod --title "GNU parset" \
 	|| echo "Warning: pod2pdf not found. Using old parset.pdf"
 
+parallel_cheat.pdf: parallel_cheat.fodt
+	libreoffice --headless --convert-to pdf parallel_cheat.fodt \
+	|| echo "Warning: libreoffice failed. Using old parallel_cheat.pdf"
+
 sem: parallel
 	ln -fs parallel sem
 
@@ -273,7 +278,8 @@ DISTCLEANFILES = parallel.1 env_parallel.1 sem.1 sql.1 niceload.1	\
 	parset.texi \
 	parallel.pdf env_parallel.pdf sem.pdf sql.pdf niceload.pdf	\
 	parallel_tutorial.pdf parallel_book.pdf parallel_design.pdf	\
-	parallel_alternatives.pdf parcat.pdf parset.pdf
+	parallel_alternatives.pdf parcat.pdf parset.pdf			\
+	parallel_cheat.pdf
 
 EXTRA_DIST = parallel sem sql niceload parcat parset env_parallel	\
 	env_parallel.ash env_parallel.bash env_parallel.csh		\

src/Makefile.in

@@ -249,7 +249,8 @@ bin_SCRIPTS = parallel sql niceload parcat parset env_parallel	\
 @DOCUMENTATION_TRUE@	parset.texi \
 @DOCUMENTATION_TRUE@	parallel.pdf env_parallel.pdf sem.pdf sql.pdf niceload.pdf	\
 @DOCUMENTATION_TRUE@	parallel_tutorial.pdf parallel_book.pdf parallel_design.pdf	\
-@DOCUMENTATION_TRUE@	parallel_alternatives.pdf parcat.pdf parset.pdf
+@DOCUMENTATION_TRUE@	parallel_alternatives.pdf parcat.pdf parset.pdf			\
+@DOCUMENTATION_TRUE@	parallel_cheat.pdf
 
 DISTCLEANFILES = parallel.1 env_parallel.1 sem.1 sql.1 niceload.1	\
 	parallel_tutorial.7 parallel_book.7 parallel_design.7		\
@@ -264,7 +265,8 @@ DISTCLEANFILES = parallel.1 env_parallel.1 sem.1 sql.1 niceload.1	\
 	parset.texi \
 	parallel.pdf env_parallel.pdf sem.pdf sql.pdf niceload.pdf	\
 	parallel_tutorial.pdf parallel_book.pdf parallel_design.pdf	\
-	parallel_alternatives.pdf parcat.pdf parset.pdf
+	parallel_alternatives.pdf parcat.pdf parset.pdf			\
+	parallel_cheat.pdf
 
 EXTRA_DIST = parallel sem sql niceload parcat parset env_parallel	\
 	env_parallel.ash env_parallel.bash env_parallel.csh		\
@@ -848,6 +850,10 @@ parset.pdf: parset.pod
 	pod2pdf --output-file $(srcdir)/parset.pdf $(srcdir)/parset.pod --title "GNU parset" \
 	|| echo "Warning: pod2pdf not found. Using old parset.pdf"
 
+parallel_cheat.pdf: parallel_cheat.fodt
+	libreoffice --headless --convert-to pdf parallel_cheat.fodt \
+	|| echo "Warning: libreoffice failed. Using old parallel_cheat.pdf"
+
 sem: parallel
 	ln -fs parallel sem
 

src/parallel.pod

@@ -1060,6 +1060,9 @@ sshlogin in sorted order.
 If used with B<--pipe --roundrobin> and the same input, the jobslots
 will get the same blocks in the same order in every run.
 
+B<-k> only affects the order in which the output is printed - not the
+order in which jobs are run.
+
 
 =item B<-L> I<recsize>
 

src/parallel_alternatives.pod

@@ -1998,6 +1998,74 @@ corresponding GNU B<parallel> command.
 
 https://github.com/k-bx/par (Last checked: 2019-02)
 
+=head2 DIFFERENCES BETWEEN parallelshell AND GNU Parallel
+
+B<parallelshell> does not allow for composed commands:
+
+  # This does not work
+  parallelshell 'echo foo;echo bar' 'echo baz;echo quuz'
+
+Instead you have to wrap that in a shell:
+
+  parallelshell 'sh -c "echo foo;echo bar"' 'sh -c "echo baz;echo quuz"'
+
+It buffers output in RAM. All commands must be given on the command
+line and all commands are started in parallel at the same time. This
+will cause the system to freeze if there are so many jobs that there
+is not enough memory to run them all at the same time.
+
+https://github.com/keithamus/parallelshell (Last checked: 2019-02)
+
+https://github.com/darkguy2008/parallelshell (Last checked: 2019-03)
+
+
+=head2 DIFFERENCES BETWEEN shell-executor AND GNU Parallel
+
+B<shell-executor> does not allow for composed commands:
+
+  # This does not work
+  sx 'echo foo;echo bar' 'echo baz;echo quuz'
+
+Instead you have to wrap that in a shell:
+
+  sx 'sh -c "echo foo;echo bar"' 'sh -c "echo baz;echo quuz"'
+
+It buffers output in RAM. All commands must be given on the command
+line and all commands are started in parallel at the same time. This
+will cause the system to freeze if there are so many jobs that there
+is not enough memory to run them all at the same time.
+
+https://github.com/royriojas/shell-executor (Last checked: 2019-02)
+
+
+=head2 DIFFERENCES BETWEEN non-GNU par AND GNU Parallel
+
+B<par> buffers in memory to avoid mixing of jobs. It takes 1s per 1
+million output lines.
+
+B<par> needs to have all commands before starting the first job. The
+jobs are read from stdin (standard input) so any quoting will have to
+be done by the user.
+
+Stdout (standard output) is prepended with o:. Stderr (standard error)
+is sendt to stdout (standard output) and prepended with e:.
+
+For short jobs with little output B<par> is 20% faster than GNU B<parallel>.
+
+http://savannah.nongnu.org/projects/par (Last checked: 2019-02)
+
+
+=head2 DIFFERENCES BETWEEN fd AND GNU Parallel
+
+B<fd> does not support composed commands, so commands must be wrapped
+in B<sh -c>.
+
+It buffers output in RAM. 
+
+It only takes file names from the filesystem as input (similar to B<find>).
+
+https://github.com/sharkdp/fd (Last checked: 2019-02)
+
 
 =head2 Todo
 
@@ -2005,16 +2073,10 @@ Url for spread
 
 https://github.com/reggi/pkgrun
 
-https://github.com/benoror/better-npm-run
+https://github.com/benoror/better-npm-run - not obvious how to use
 
 https://github.com/bahmutov/with-package
 
-https://github.com/spion/npm-parallel
-
-https://github.com/royriojas/shell-executor
-
-https://github.com/darkguy2008/parallelshell
-
 https://github.com/xuchenCN/go-pssh
 
 https://github.com/amritb/with-this.git
@@ -2028,7 +2090,7 @@ https://github.com/Julian/Verge
 
 There are certain issues that are very common on parallelizing
 tools. Here are a few stress tests. Be warned: If the tool is badly
-coded it may overload you machine.
+coded it may overload your machine.
 
 
 =head2 MIX: Output mixes
@@ -2069,6 +2131,33 @@ This test stresses whether output mixes.
   # and there should only be a single line per job
 
 
+=head2 STDERRMERGE: Stderr is merged with stdout
+
+Output from stdout and stderr should not be merged, but kept separated.
+
+This test shows whether stdout is mixed with stderr.
+
+  #!/bin/bash
+
+  paralleltool="parallel -j0"
+
+  cat <<-EOF > mycommand
+  #!/bin/bash
+
+  echo stdout
+  echo stderr >&2
+  echo stdout
+  echo stderr >&2
+  EOF
+  chmod +x mycommand
+
+  # Run one job
+  echo |
+    $paralleltool ./mycommand > stdout 2> stderr
+  cat stdout
+  cat stderr
+
+
 =head2 RAM: Output limited by RAM
 
 Some tools cache output in RAM. This makes them extremely slow if the