10 tiny helper scripts for devs!

Ben Winding — Mon, 24 Aug 2020 06:12:14 +0000

Notes

This is a collection of tiny scripts that you can execute through the terminal.
These are designed for Ubuntu (with zsh), but may work on other unixy systems
Some are stolen scripts, other's are original!
Scripts are in various languages e.g; #!/usr/bin/env ruby
These are part of a dotfiles collection:
- Which is basically a folder on your system for organising personal scripts and terminal configuration.
- Here's the source repo: https://github.com/benwinding/dotfiles

10 tiny helper scripts

(1) `git-undo`

#!/bin/sh

# Undo your last commit  (in current folder), but don't throw away your changes

git reset --soft HEAD^

(2) `gclonecd https://github.com/reactjs/react-modal`

#!/bin/zsh

# Clones git repo and cd's into it
gclonecd() {
  git_dir="$(basename "$1" .git)"
  git_dir_resolved=${2:-$git_dir}
  git clone "$@" && cd "$git_dir_resolved";
}

(3) `killport 3000`

#!/bin/zsh

# Kills a process running on a specified tcp port
killport() {
  echo "Killing process on port: $1"
  fuser -n tcp -k $1;
}

(4) `mvp ./this-dir ./some/other/new/dir`

#!/bin/zsh

# Move and make parents

function mvp () {
    source="$1"
    target="$2"
    target_dir="$(dirname "$target")"
    mkdir --parents $target_dir; mv $source $target
}

(5) `dos2unixd ./dir`

#!/bin/zsh

# Dos2unix a whole directory (crlf to lf)
dos2unixd() {
  find $1 -type f -print0 | xargs -0 dos2unix
}

(6) `docker-kill-all`

# Kills all docker containers running
alias docker-kill-all='docker kill `docker ps -aq`'

(7) `docker-rm-all`

# Deletes all docker containers
alias docker-rm-all='docker rm `docker ps -aq`'

(8) `git-delete-local-merged`

#!/bin/bash
#
# Delete all local branches that have been merged into HEAD. Stolen from
# our favorite @tekkub:
#
#   https://plus.google.com/115587336092124934674/posts/dXsagsvLakJ

branches=`git branch --merged master | grep -v '\*\|master\|unstable\|develop'`
[ -z "$branches" ] && printf '\nNo merged branches to delete...\n' && exit;
command="git branch -d $branches"

echo ''
printf '%s\n' "$branches"
echo ''
printf 'Delete merged branches locally? Press [Enter] to continue...'
read _

echo ''
echo 'Safely deleting merged local branches...'
echo 'Running command: '$command

`$command`

(9) `git-delete-remote-merged`

#!/bin/bash

remote='origin'
echo "Will delete the following branches from [$remote]:"
branches=`git branch -r --merged master | grep -v '\*\|master\|unstable\|develop'`
[ -z "$branches" ] && printf '\nNo merged branches to delete...\n' && exit;

echo ''
printf '%s\n' "$branches"
echo ''
printf 'Delete merged remote branches from '$remote'? Press [Enter] to continue'
read _
echo ''
echo 'Safely deleting merged remote branches...'

echo $branches | sed -e "s:$remote/::g" | xargs -t git push $remote -d

(10) `github-open`

#!/usr/bin/env ruby

# Opens the current github repository in the default browser
remotes = `git remote`
hasNoRemotes = remotes.size < 2
if hasNoRemotes then 
  return
end
repolink = `git remote get-url origin`
if repolink.include?("git@github.com:") then 
  # Converts from ssh format to https format if necessary

  # git@github.com:benwinding/dotfiles
  # https://github.com/benwinding/dotfiles
  repolink = repolink.gsub("git@github.com:", "https://github.com/")
end

`xdg-open #{repolink}`

I highly recommend anyone who isn't familiar with shell scripting to checkout holman's dotfiles which is targetted towards make users. Or my own fork ben's dotfiles which is targetted towards ubuntu users.

When you begin writing and maintaining your own little library of scripts and snippets, you'll be amazed at what you can automate and accomplish.

Don't ALWAYS quick-return from functions

Ben Winding — Fri, 13 Apr 2018 13:17:50 +0000

There are two main styles of returning from a function in a program. Both styles are almost diametrically-opposed, but have their uses.

Single Return

An example of nested single-returning. This is hard to read and keep track of the levels of scope.

int GetCost(request) {
    int cost = 0;
    if (request.Important) {
        if (request.HasDiscount) {
            if (request.IsMember) {
                cost = 10;
            }
            else {
                cost = 12;
            }
        }
        else {
            cost = 14;
        }
    }
    else {
        cost = 20;
    }
    return cost;
}

Quick Return

Now arguably the code can be made simpler by using the prophetic "Quick Return!" method. This has the effect of returning out of the function as soon as possible, making the code easier to reason about. Also, by unravelling the if-statements into a neat stack, the code becomes much easier to read.

int GetCost(request) {
    if (!request.Important) 
        return 20;
    else if (!request.HasDiscount) 
        return 14;
    else if (!request.IsMember) 
        return 12;
    else
        return 10;
}

However ... Memory Leaks

The reason quick returns were not encouraged in earlier days of programming is a lack of garbage collection. During the execution of a function, memory may be allocated. So a simplify this, the function is given only one exit point, to ensure all memory in the function is deallocated before the function returns.

The following is another version of the single return function (with an added checking object). Cleaner and easier to read with still one return statement (and a little clean up).

int GetCost(request) {
    Checker checker = new Checker(request);
    int cost = 0;
    if (!checker.Important) 
        cost = 20;
    else if (!checker.HasDiscount) 
        cost = 14;
    else if (!checker.IsMember) 
        cost = 12;
    else 
        cost = 10;
    delete checker;
    return cost;
}

But memory might not be the only thing that needs to be cleaned up at the end of a function's execution. There are other things that might need to be 'freed up' like:

Hardware resources
Object mutation locks
Network connections

By returning only once within a function, the chance of leaving one of these resources open/locked is greatly reduced.

So, the older method of single return is not completely useless! And depending on the language and environment, quick-returns may not always be the best solution.

DEV Community: Ben Winding

10 tiny helper scripts for devs!

Notes