Change all whoami calls for $USER variable

This avoid spawning additional processes, as the $USER variable will
**always** contain the current logged-in user.

lib/completion.zsh

@@ -27,9 +27,9 @@ zstyle ':completion:*:*:*:*:*' menu select
 zstyle ':completion:*:*:kill:*:processes' list-colors '=(#b) #([0-9]#) ([0-9a-z-]#)*=01;34=0=01'
 if [ "$OSTYPE[0,7]" = "solaris" ]
 then
-  zstyle ':completion:*:*:*:*:processes' command "ps -u `whoami` -o pid,user,comm"
+  zstyle ':completion:*:*:*:*:processes' command "ps -u $USER -o pid,user,comm"
 else
-  zstyle ':completion:*:*:*:*:processes' command "ps -u `whoami` -o pid,user,comm -w -w"
+  zstyle ':completion:*:*:*:*:processes' command "ps -u $USER -o pid,user,comm -w -w"
 fi
 
 # disable named-directories autocompletion

plugins/systemadmin/systemadmin.plugin.zsh

@@ -30,7 +30,7 @@ function retlog() {
 }
 
 alias ping='ping -c 5'
-alias clr='clear;echo "Currently logged in on $(tty), as $(whoami) in directory $(pwd)."'
+alias clr='clear;echo "Currently logged in on $(tty), as $USER in directory $(pwd)."'
 alias path='echo -e ${PATH//:/\\n}'
 alias mkdir='mkdir -pv'
 # get top process eating memory

themes/adben.zsh-theme

@@ -89,9 +89,8 @@ function precmd {
 
 # Context: user@directory or just directory
 prompt_context () {
-    local user=`whoami`
-    if [[ "$user" != "$DEFAULT_USER" || -n "$SSH_CLIENT" ]]; then
-        echo -n "${PR_RESET}${PR_RED}$user@%m${PR_RESET}${PR_BRIGHT_YELLOW}%~%<<${PR_RESET}"
+    if [[ "$USER" != "$DEFAULT_USER" || -n "$SSH_CLIENT" ]]; then
+        echo -n "${PR_RESET}${PR_RED}$USER@%m${PR_RESET}${PR_BRIGHT_YELLOW}%~%<<${PR_RESET}"
     else
         echo -n "${PR_RESET}${PR_BRIGHT_YELLOW}%~%<<${PR_RESET}"
     fi

themes/agnoster.zsh-theme

@@ -60,10 +60,8 @@ prompt_end() {
 
 # Context: user@hostname (who am I and where am I)
 prompt_context() {
-  local user=`whoami`
-
-  if [[ "$user" != "$DEFAULT_USER" || -n "$SSH_CLIENT" ]]; then
-    prompt_segment black default "%(!.%{%F{yellow}%}.)$user@%m"
+  if [[ "$USER" != "$DEFAULT_USER" || -n "$SSH_CLIENT" ]]; then
+    prompt_segment black default "%(!.%{%F{yellow}%}.)$USER@%m"
   fi
 }
 

themes/flazz.zsh-theme

-if [ "$(whoami)" = "root" ]
+if [ "$USER" = "root" ]
 then CARETCOLOR="red"
 else CARETCOLOR="blue"
 fi

themes/obraun.zsh-theme

-if [ "$(whoami)" = "root" ]; then CARETCOLOR="red"; else CARETCOLOR="blue"; fi
+if [ "$USER" = "root" ]; then CARETCOLOR="red"; else CARETCOLOR="blue"; fi
 
 local return_code="%(?..%{$fg[red]%}%? ↵%{$reset_color%})"
 

themes/re5et.zsh-theme

-if [ "$(whoami)" = "root" ]; then CARETCOLOR="red"; else CARETCOLOR="magenta"; fi
+if [ "$USER" = "root" ]; then CARETCOLOR="red"; else CARETCOLOR="magenta"; fi
 
 local return_code="%(?..%{$fg_bold[red]%}:( %?%{$reset_color%})"
 

themes/sunrise.zsh-theme

@@ -10,7 +10,7 @@ Y=$fg_no_bold[yellow]
 B=$fg_no_bold[blue]
 RESET=$reset_color
 
-if [ "$(whoami)" = "root" ]; then
+if [ "$USER" = "root" ]; then
     PROMPTCOLOR="%{$R%}" PREFIX="-!-";
 else
     PROMPTCOLOR="" PREFIX="---";

themes/ys.zsh-theme

@@ -33,7 +33,7 @@ ${git_info} \
 %{$fg[white]%}[%*]
 %{$terminfo[bold]$fg[red]%}$ %{$reset_color%}"
 
-if [[ "$(whoami)" == "root" ]]; then
+if [[ "$USER" == "root" ]]; then
 PROMPT="
 %{$terminfo[bold]$fg[blue]%}#%{$reset_color%} \
 %{$bg[yellow]%}%{$fg[cyan]%}%n%{$reset_color%} \