fix: POSIX does not support head byte count

Test done on OpenBSD for compatibility with the POSIX specification,
also becoming a new supported system.

README.md

@@ -28,7 +28,7 @@ Configuration and scripts targeting:
 - Portability:
   - POSIX compliant code
   - Drop-in configuration files
-  - Tested in Qubes OS Dom0, Debian, Fedora
+  - Tested in Qubes OS Dom0, Debian, Fedora, OpenBSD
 - Tasks:
   - GUI: x11, gtk
   - SCM: git, tig, git-shell

files/git/.config/git/config

@@ -77,7 +77,7 @@
 	; Signed tags and commits
 	stag = "!sh -c '\
 		commit_id=\"$(git rev-parse --verify \"$@\")\"; \
-		tag_name=\"signed_tag_for_$(echo $commit_id | head -c 8)\"; \
+		tag_name=\"signed_tag_for_$(echo $commit_id | cut -c 1-8)\"; \
 		git tag -s \"$tag_name\" \
 			-m \"Tag for commit $commit_id\" \"$commit_id\"; \
 		echo \"$tag_name\"'" -

files/git/.local/bin/git-server-setup

@@ -39,7 +39,7 @@ chmod -R 0755 "$git_home/git-shell-commands"
 
 git config --system receive.updateServerInfo true
 git config --system receive.advertisePushOptions true
-nonce="$(head /dev/urandom | LC_ALL=C tr -dc 'A-Za-z0-9!#$%&'\''()*+,-./:;<=>?@[\]^_`{|}~' | head -c 256)"
+nonce="$(head /dev/urandom | LC_ALL=C tr -dc 'A-Za-z0-9!#$%&'\''()*+,-./:;<=>?@[\]^_`{|}~' | cut -c 1-256)"
 git config --system receive.certNonceSeed "$nonce"
 
 chown -R "$git_user":"$git_user" "$git_home"

files/sh/.config/bash/bashrc

@@ -46,7 +46,7 @@ _reset_line() {
 
   local termios cur_y
   ## Ask the terminal for any pending (line buffered) input.
-  termios=$(stty --save) && stty -icanon && stty "$termios"
+  termios=$(stty -g) && stty -icanon && stty "$termios"
   ## On pending input, assume it's been echoed and we're not in first column.
   ## Otherwise ask the terminal for current column and read it from input.
   if read -t 0 || {

files/sh/.config/sh/profile

@@ -94,12 +94,19 @@ KDEHOME="$XDG_CONFIG_HOME/kde"
 #KDEROOTHOME="/root/.config/kde"
 INPUTRC="$BASHDIR/inputrc"
 if has less; then
-  if test "$(less -V | awk -F '[ .]' 'NR==1 {print $2}')" -ge 582; then
+  lesskey_src=0
+  less_version="$(less -V | awk -F '[ .]' 'NR==1 {print $2}')"
+  case "${less_version}" in
+    ""|*[!0-9]*) ;;
+    *) if test "${less_version}" -ge 582; then lesskey_src=1; fi;;
+  esac
+  if test "${lesskey_src}" = "1"; then
     LESSKEY="$XDG_CONFIG_HOME/less/lesskey"
   elif has lesskey; then
     LESSKEY="$XDG_CONFIG_HOME/less/lesskey-old"
     lesskey -o "$LESSKEY" "$XDG_CONFIG_HOME/less/lesskey"
   fi
+  unset lesskey_src less_version
 fi
 export GTK2_RC_FILES KDEHOME KDEROOTHOME INPUTRC LESSKEY
 

files/sh/.config/sh/shrc

@@ -38,7 +38,9 @@ if has lsblk; then
   alias lsblk='lsblk -o $_lsblk_options'
   alias lsblku='lsblk -o $_lsblk_options,UUID,PARTUUID'
 fi
-if ! grep --color 2>&1 | grep -q "unrecognized option"; then
+if ! grep --color 2>&1 | grep -qE "(unrecognized|unknown) option" &&
+   ! grep --exclude 2>&1 | grep -qE "(unrecognized|unknown) option"
+then
   alias grep="grep --exclude='.*.swp' --exclude='*~' --color=auto"
 fi
 alias fgrep="grep -F"
@@ -210,7 +212,7 @@ _git_prompt_info(){
   fi
   ref="$(git symbolic-ref HEAD 2>/dev/null | cut -d '/' -f3)"
   test "${ref-}" || ref="$(git describe --tags --exact-match HEAD 2>/dev/null)"
-  test "${ref-}" || ref="$(git rev-parse HEAD 2>/dev/null | head -c 7)"
+  test "${ref-}" || ref="$(git rev-parse HEAD 2>/dev/null | cut -c 1-7)"
   test "${ref-}" || return
   # shellcheck disable=2039,3003
   case "${TERM-}" in

files/sh/.config/zsh/.zprofile

@@ -8,5 +8,7 @@
 ## some distributions such as Qubes, Whonix, Debian, Gentoo ship files to
 ## /etc/profile.d.
 
-emulate sh -c "source /etc/profile"
+if test -r /etc/profile; then
+  emulate sh -c "source /etc/profile"
+fi
 . "$HOME/.profile"

files/sh/.config/zsh/.zshrc

@@ -71,7 +71,7 @@ if test "${color_prompt-}" = "yes"; then
   autoload -U colors && colors
   [[ "${COLORTERM-}" == (24bit|truecolor) || "${terminfo[colors]}" -eq '16777216' ]] || zmodload zsh/nearcolor
 
-  PS1="\$(resize-terminal)%F{magenta}[%{$usercolor%}%n@%M%F{reset_color%} %{$dircolor%}%50<...<%~%<<%F{reset_color%}\$(_git_prompt_info)%F{magenta}]%F{reset_color}${newline-}${ps1_symbol} "
+  PS1="\$(resize-terminal)%F{magenta}[%{$usercolor%}%n@%m%F{reset_color%} %{$dircolor%}%50<...<%~%<<%F{reset_color%}\$(_git_prompt_info)%F{magenta}]%F{reset_color}${newline-}${ps1_symbol} "
   RPS1="%(?..(%{"$'\e[31m'"%}%?%{$reset_color%}%)%<<)"
 else
   PS1="\$(resize-terminal)[%n@%M %~\$(_git_prompt_info)]${newline}${ps1_symbol} "