---
layout: page
title: "TIL: Useful code snippets"
lang: en
ref: til
---

### Bash variables

```shell
$ which git
/run/current-system/sw/bin/git
$ readlink $(!!)
readlink $(which git)
/nix/store/5bgr1xpm4m0r72h9049jbbhagxdyrnyb-git-2.28.0/bin/git
```

### Git custom work-tree checkout

```shell
git --work-tree=/path/to/outputdir checkout HEAD -- .
```
### Search in Git

Search log messages

```shell
git log --grep='Build 0051'
```

Search content in git history

```shell
git grep 'Build 0051' $(git rev-list --all)
```
### Find broken symlinks

```shell
find . -xtype l
```

### Kernel version
```shell
uname -r
```
### Sending email through the command line

```shell
mail eu@euandre.org -s "This is the subject" -aFrom:eu@euandre.org <<< 'This is the message'
```

### Git bisecting

Automatic Git bisect

```shell
git bisect start e1fd0a817d192c5a5df72dd7422e36558fa78e46 HEAD
git bisect run sh -c 'git clean -ffdx && ./bootstrap && ./configure --localstatedir=/var && make && git checkout'
```

### UNIX searching commands

```shell
$ which gcc
$ locate signal.h
$ updatedb # add to cron?
```

### Guix contributing

```shell
$ cd ~/dev/guix/guix/
$ git clean -ffdx
$ guix environment guix # guix environment guix --ad-hoc help2man git strace
$ ./bootstrap
$ ./configure --localstatedir=/var
$ make
$ ./pre-inst-env guix describe
$ ./pre-inst-env guix show $PKG
$ ./pre-inst-env guix build $PKG
$ ./pre-inst-env guix lint $PKG
```

v2:
```shell
guix environment --pure guix --ad-hoc help2man git strace -- sh -c "./bootstrap && ./configure --localstatedir=/var && make"
```

v3:
```shell
$ guix environment --pure guix --ad-hoc help2man git stract
$ ./bootstrap
$ ./configure --localstatedir=/var
$ make
$ ./pre-inst-env guix build $PKG
$ ./pre-inst-env guix lint $PKG
$ ./pre-inst-env guix refresh --list-dependent $PKG
$ ./pre-inst-env guix build --rounds=2 $PKG
$ ./etc/ident-code.el $PKG
```

### git mail patches

Check the [guix-devel thread][0] on
named "Re: [External] Re: New outreachy participant introduction".

[0]: https://lists.gnu.org/archive/html/guix-devel/2019-10/msg00093.html

### Flutter Dart `patchelf`

```shell
patchelf --set-interpreter $(cat $NIX_CC/nix-support/dynamic-linker) /home/andreh/dev/misc/flutter/bin/cache/dart-sdk/bin/dart
```

### builds.sr.ht environment variables

[https://builds.sr.ht/~euandreh/job/68005](https://builds.sr.ht/~euandreh/job/68005).

### `C-c M-m` in message-mode for creating `cut here` sections

Or run the `scissors` function.

### Software Recomendations StackExchange exists

[https://softwarerecs.stackexchange.com/](https://softwarerecs.stackexchange.com/).

### GPG key search

```shell
gpg --search-key eu@euandre.org
```

### Git Annex wanted

```shell
git annex wanted . 'exclude=Banshee/old-musics/* and exclude=attic/videos/* and exclude=Photos/*'
```

### Useful keybindings
- `SPC v` for region selection
- `SPC j s` to split sexp
- `mod-shift-space` reset layout

## Acknowledgements

Shameless rip-off of [Anna e só](https://til.flourishing.stream/).