Bash talk.

content/blog/2021-bash.md

@@ -0,0 +1,140 @@
+---
+Title: How I use bash
+Date: 2021-06-04 06:20:00
+Summary: This is how I use bash, as I presented it at « En attendant la PyCon Fr ».
+---
+
+# bash
+
+I presented this as a lightnign talk at [« En attendant la PyCon
+Fr »](https://discuss.afpy.org/t/en-attendant-la-pyconfr-du-15-avril-2021/222/),
+there's [a video
+(in french)](https://dl.afpy.org/en-attendant-la-pycon-fr-2020-2021/2021-04%20Bash%20-%20trucs%20&%20astuces%20-%20mdk.mp4).
+
+
+How to read:
+
+When I write `^A` it mean I press `Ctrl-A`, which is noted `C-a`
+(bash/emacs notation).
+
+`M-a` means `Meta-a` (it's left alt on current keyboards).
+
+
+## I avoid singleline prompt
+
+Because of the following issue:
+
+    PS1='$ '
+    printf "pouette"
+    ls^A
+    ls -l^A
+
+Issue is: readline have two ways to move at the beginning of a line,
+and have no way to know where the cursor is, and assume the line start
+at column 0.
+
+
+## Easy, daily, shortcuts
+
+### Killing and Yanking from the killing stack
+
+- `C-a C-k`: Move to the beginning, then kill the line.
+- `C-y`, `M-y`: Yank and yank pop.
+
+Example:
+
+```
+$ git push origin HEAD^A^Kgit commit -m "FIX"^A^Kgit add -u
+C-y
+Enter
+C-y
+M-y
+Enter
+```
+
+### Moving
+
+- `C-a` (beginning of line) `C-e` (end of line).
+- `C-p` and `C-n`: like up and down arrows, to browse history.
+
+Avoid `C-pC-pC-pC-pC-p` or `↑↑↑↑↑↑`, use `C-r`.
+
+
+### Fixing typos
+
+- `C-t` (swap chars), `M-t` (swap words).
+- `M-l`, `M-u`, `M-c` (lowercase, uppercase, capitalize)
+- `C-g` (abort)
+
+
+### Cleaning
+
+`C-l` (clear screen). Oh, if it's not enough, like after killing `sl`,
+use `reset`, so `ENTER reset ENTER` to ensure you type it in a clear
+line, or `C-a C-k reset ENTER` to avoid executing blindly.
+
+
+### sudo !!
+
+```bash
+$ man bash | grep '!!'
+!!     Refer to the previous command.  This is a synonym for `!-1'.
+```
+
+so:
+```
+$ apt upgrade
+E: ... are you root?
+$ sudo !!
+sudo apt upgrade
+...
+```
+
+### Globstar
+
+`shopt -s globstar`:
+
+```
+$ rm **/*.md
+```
+
+same as:
+
+```
+$ find -name '*.md' -delete
+```
+
+example:
+
+```
+sed -i '1i#!/usr/bin/env python3' **/*.py
+```
+
+
+## Other shortcuts I use
+
+And I like them for the nice symetry:
+
+- `C-f` to move forward a char, `M-f` to move forward a word.
+- `C-b` to move backward a char, `M-b` to move backward a word.
+- `C-d` to delete a char, `M-d` to delete a word.
+
+
+## Pipelines for the win!
+
+```
+$ man bash | grep -C1 C-a
+Commands for Moving
+    beginning-of-line (C-a)
+        Move to the start of the current line.
+```
+
+## Subshells for the win!
+
+```
+emacs $(git grep -l PATTERN)
+```
+
+# Bonus
+
+Those are the same in emacs, save brain space, use emacs.