Add minor files

random-bash.md

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+# Random bash
+
+Here's random useful bash stuff:
+
+## Check if program is installed
+
+Checks if `$1` is installed
+
+```bash
+#!/usr/bin/env bash
+command_exists() { type "$1" &> /dev/null; }
+
+if command_exists "$1"; then
+    echo "$1 installed"
+else
+    echo "$1 not installed"
+    exit 1
+fi
+```
+
+### Check which package manager is installed
+
+```bash
+#!/usr/bin/env bash
+command_exists() { type "$1" &> /dev/null; }
+
+if command_exists "apt-get"; then
+    PM="apt-get"
+elif command_exists "yum"; then
+    PM="yum"
+elif command_exists "pacman"; then
+    PM="pacman"
+elif command_exists "zypper"; then
+    PM="zypper"
+elif command_exists "emerge"; then
+    PM="emerge"
+elif command_exists "apk"; then
+    PM="apk"
+else
+    >&2 echo "Unsupported: unknown package manager"
+    exit 1
+fi
+
+echo "Package manager: ${PM}"
+```
+
+## Check if root
+
+This exits with and error message if it's run as root.
+
+```bash
+#!/bin/bash
+if [ $(whoami) != "root" ]; then
+    >&2 echo Rerun as non-root user
+    exit 1
+fi
+```

test.bash

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+#!/bin/bash
+command_exists() { type "$1" &> /dev/null; }
+
+if command_exists "apt-get"; then
+    PM="apt-get"
+elif command_exists "yum"; then
+    PM="yum"
+fi
+
+echo $PM