import recipes: todo add to site

todo-recipes/ffmpeg.md

@@ -0,0 +1,25 @@
+# ffmpeg
+
+Everyone's favourite impossible-to-use tool
+
+Coordinates are counted from the top left corner like so:
+
+```
+0- +x
+|
++y
+```
+
+## Add text
+
+This puts the text in a transparent box with opacity 0.25.
+
+```
+ffmpeg -i input.mp4 -vf drawtext="fontfile=/usr/share/fonts/adobe-source-sans-pro/SourceSansPro-Regular.otf: text='THE TEXT': fontcolor=white: fontsize=250: box=1: boxcolor=black@0.25: boxborderw=5: x=(w-text_w)/2: y=(h-550)" -codec:a copy output.mp4
+```
+
+## Download a m3u8 playlist
+
+```
+ffmpeg -protocol_whitelist file,http,https,tcp,tls,crypto -i 'https://host/playlist.m3u8' -c copy video.mp4
+```

todo-recipes/gifs.md

@@ -0,0 +1,13 @@
+# GIFs
+
+## MP4 to GIF
+
+```bash
+ffmpeg -i input.mp4 -vf "fps=10,scale=320:-1:flags=lanczos" -c:v pam -f image2pipe - | convert -delay 10 - -loop 0 -layers optimize output.gif
+```
+
+## GIF to MP4
+
+```bash
+ffmpeg -f gif -i infile.gif outfile.mp4
+```

todo-recipes/git.md

@@ -0,0 +1,24 @@
+# git
+
+everyone's favourite VCS
+
+## what's going on between these two branches
+
+relevant: `man gitrevisions`
+
+### print commits in develop but not in main
+
+```
+git log origin/main..origin/develop
+```
+
+## git reset --hard a directory
+
+[source](https://stackoverflow.com/a/15404733)
+
+```
+git restore --source=HEAD --staged --worktree -- aDirectory
+# or, shorter
+git restore -s@ -SW  -- aDirectory
+```
+

todo-recipes/latex.md

@@ -0,0 +1,14 @@
+# LaTeX
+
+## Enable/disable page numbering
+
+```latex
+% disable numbering on this page
+\thispagestyle{empty}
+
+% turn it off entirely 🦃
+\pagenumbering{gobble}
+
+% turn it back on
+\pagenumbering{arabic}
+```

todo-recipes/nix.md

@@ -0,0 +1,31 @@
+# Nix
+
+A very nice package management system with some confusing command syntax.
+
+## Investigate a derivation
+
+[nix-diff](https://github.com/Gabriel439/nix-diff) can be used to find why
+derivations are different.
+
+```
+nix-diff /nix/store/...-a.drv /nix/store/...-b.drv
+```
+
+Find the derivation for a given nix store path:
+
+```
+nix-store -q --deriver /nix/store/...-name-0.0.0
+```
+
+Dump a derivation as JSON:
+
+```
+nix show-derivation /nix/store/...-a.drv
+```
+
+Find why a derivation has a dependency:
+
+```
+nix why-depends -a -f default.nix 'attrnameHere' 'theDepAttrName'
+```
+

todo-recipes/pdf.md

@@ -0,0 +1,22 @@
+# pdf
+
+## Pull a page range from a pdf
+
+```bash
+pdftk {filename.pdf} cat {page ranges} output {output.pdf}
+```
+
+## Get metadata of a pdf
+
+```bash
+pdfinfo {filename.pdf}
+```
+
+## Concatenate a bunch of pdfs
+
+Note: I think this overwrites the last input file if you forget to specify an output!!
+
+```bash
+pdfunite {file.pdf...} {output.pdf}
+```
+

todo-recipes/selinux.md

@@ -0,0 +1,9 @@
+# SELinux
+
+`ausearch -m avc` to find denials. If there are none, that's probably because some distro maintainer decided that the denial should be silent:
+
+`semodule -DB` turns on `dontaudit` events, `semodule -B` turns them back off.
+
+When trying to get things to work correctly with `audit2allow`, skip the 15 minutes of doing things over and over triggering different denials and running `audit2allow -M mymodule < fails; semodule -i mymodule.pp` by just doing a quick `setenforce 0` before doing it once. All of the actions (AVCs?) in creating a file will show up in the log in one shot. Obviously turn on enforcing mode afterwards.
+
+When in doubt, consult the [colouring book](https://people.redhat.com/duffy/selinux/selinux-coloring-book_A4-Stapled.pdf).

todo-recipes/svg-to-png.md

@@ -0,0 +1,5 @@
+# SVG rasterization (to PNG)
+
+```bash
+rsvg-convert  --keep-aspect-ratio -w 1024 -h 1024 infile.svg outfile.png
+```

todo-recipes/vim.md

@@ -0,0 +1,7 @@
+# Vim incantations
+
+## Delete lines matching
+
+`:g/<pattern>/<cmd>` executes an ex command `<cmd>` on lines matching
+`<pattern>`. Use the command `d` to delete the lines.
+

todo-recipes/word.md

@@ -0,0 +1,10 @@
+# MS Word
+
+To execute a macro, press `Alt+F11` for the macro editor, then `Ctrl+G` for the
+immediate window.
+
+### Convert automatic numbers to manual numbering
+
+```vb
+ActiveDocument.ConvertNumbersToText
+```