https://github.com/karlhorky/command-line-tricks
A collection of useful command line tricks
https://github.com/karlhorky/command-line-tricks
command-line terminal
Last synced: 3 months ago
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A collection of useful command line tricks
- Host: GitHub
- URL: https://github.com/karlhorky/command-line-tricks
- Owner: karlhorky
- Created: 2015-10-12T10:07:12.000Z (over 9 years ago)
- Default Branch: main
- Last Pushed: 2024-10-11T09:08:55.000Z (9 months ago)
- Last Synced: 2024-10-26T01:20:55.353Z (8 months ago)
- Topics: command-line, terminal
- Homepage:
- Size: 12.7 KB
- Stars: 4
- Watchers: 2
- Forks: 1
- Open Issues: 1
-
Metadata Files:
- Readme: readme.md
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README
# Command Line Tricks
A collection of useful command line tricks
## Create File with Content
To create a file including content (overwriting the file if it exists), use `echo` with the `-e` flag (to allow for escape sequences like the `\n` newline) and redirect to a file with `>`:
```bash
echo -e 'abc\ndef' > 1.txt
```
Now `1.txt` will include the following content:
```
abc
def
```
To make multi-line content more readable, use `cat` with a heredoc tag like `EOF`:
```bash
cat << EOF > main.ts
import { add } from './add.js';
console.log(add(2,3));
EOF
```
## FFmpeg: Combine two video files
Combine two video files using [FFmpeg](https://ffmpeg.org/)
```bash
ls video1.mp4 video2.mp4 | while read line; do echo file \'$line\'; done | ffmpeg -protocol_whitelist file,pipe -f concat -i - -c copy output.mp4
```
Source: [How to concatenate two MP4 files using FFmpeg? (Answer) | Stack Overflow](https://stackoverflow.com/a/61151377/1268612)
## Find and Replace in Git Remote
Sometimes you may want to search and replace within your Git remote - for example, if you change your username on GitHub. This is a command to do it (replaces `OldUsername` with `NewUsername`):
```sh
git remote set-url origin $(current_origin=$(git remote get-url origin --push) && echo ${current_origin/OldUsername/NewUsername})
```
## gzip web assets
Loop over CSS, JS, EOT, SVG and TTF files and gzip them into a folder named `gzipped`.
`gzip-web-assets.sh`
```bash
#!/usr/bin/env bash
# Usage:
# $ ./gzip-web-assets.sh
mkdir gzipped
for file in $(find . -type f -depth 1 | egrep "\.(css|js|eot|svg|ttf)$") ; do
gzip -c --best $file > gzipped/$file
done
```
## Set zsh custom tab title
To set a custom terminal tab title with zsh, configure [the zsh `precmd` and `preexec` hook functions](https://zsh.sourceforge.io/Doc/Release/Functions.html#Hook-Functions) in `.zshrc`:
`~/.zshrc`
```bash
# Disable auto-setting terminal title.
DISABLE_AUTO_TITLE="true"
function precmd () {
echo -ne "\033]0;Custom title: $(print -rD $PWD)\007"
}
precmd
function preexec () {
print -Pn "\e]0;🚀 $(print -rD $PWD) $1 🚀\a"
}
```
This will change the tab title as such:
1. Show the `Custom title:` prefix before the present working directory
2. When a foreground program is running, rocket emojis will appear at the beginning and end of the prompt to show a visual indicator that something is running
https://github.com/user-attachments/assets/535b243c-3f4b-4b85-8a96-d1766ab8d000
To use this with [Ghostty](https://ghostty.org/), disable Ghostty's built-in shell integration using [`shell-integration-features = no-title`](https://ghostty.org/docs/config/reference#shell-integration-features):
`~/Library/Application Support/com.mitchellh.ghostty/config`
```ini
# Disable Ghostty built-in tab title shell integration
# https://ghostty.org/docs/config/reference#shell-integration-features
shell-integration-features = no-title
```
## Wrap command and exit based on stdout
To wrap a command and exit based on stdout from the command, loop over each line of the stdout to look for the message. If the message is found, set a variable to `true` and exit with code `1`:
```bash
pnpm install | { has_ignored_build_scripts=false; while IFS= read -r line; do echo "$line"; [[ "$line" == *"Ignored build scripts:"* ]] && has_ignored_build_scripts=true; done; [[ "$has_ignored_build_scripts" = false ]]; }
```
Source: [Fail `pnpm install` on pnpm v10 ignored build scripts](https://github.com/karlhorky/pnpm-tricks#fail-pnpm-install-on-pnpm-v10-ignored-build-scripts)