Replace ~ with ${HOME}

Linux-instructions.md

@@ -22,7 +22,7 @@ With most desktop-oriented distributions, double-clicking each font file in the
 ```bash
 #!/bin/bash
 
-fonts_dir="~/.local/share/fonts"
+fonts_dir="${HOME}/.local/share/fonts"
 if [ ! -d ${fonts_dir} ]; then
     echo "mkdir -p $fonts_dir"
     mkdir -p ${fonts_dir}
@@ -31,7 +31,7 @@ else
 fi
 
 for type in Bold Light Medium Regular Retina; do
-    file_path="~/.local/share/fonts/FiraCode-${type}.ttf"
+    file_path="${HOME}/.local/share/fonts/FiraCode-${type}.ttf"
     file_url="https://github.com/tonsky/FiraCode/blob/master/distr/ttf/FiraCode-${type}.ttf?raw=true"
     if [ ! -e ${file_path} ]; then
         echo "wget -O $file_path $file_url"