Added optional feature to show non-zero exit codes in prompt

README.md

@@ -45,6 +45,18 @@ If you just name a path, the shell will assume you intended to change directorie
 ajohnson@helios:~ % git/zsh
 ajohnson@helios:~/git/zsh [add_readme]% 
 ```
+#### SHOW_NZ_EXIT
+This option will display exit codes of the previous command at the beginning of your prompt, but only when the exit code is non-zero. If the previous command returns 0, then your prompt will not show any exit code.
+```
+ajohnson@helios:~ % 
+ajohnson@helios:~ % true
+ajohnson@helios:~ % false
+1:ajohnson@helios:~ % 
+1:ajohnson@helios:~ % true
+ajohnson@helios:~ %
+ajohnson@helios:~ % zsh -c "exit 42"
+42:ajohnson@helios:~ % 
+```
 #### cd Search and Replace
 You can substitute one word for another in your current working directory by using the cd syntax:
 ```
@@ -64,7 +76,6 @@ ajohnson@helios:~/git/heatbot [rewrite]% git checkout dev
 Switched to branch 'dev'
 Your branch is up to date with 'origin/dev'.
 ajohnson@helios:~/git/heatbot [dev]% 
-
 ```
 
 ## Epilogue

example_configs/zsh.conf

@@ -8,6 +8,7 @@ HISTORY_NO_DUPS=true		#Ignore duplicate back-to-back commands in shell history
 # Prompt Style
 PROMPT_STYLE=bsd2		#Valid options: bsd, bsd2, ar5
 COMPLETION_STYLE=bash		#ZSH "automenu" option toggle - Valid options: bash, zsh (defaults to bash)
+SHOW_NZ_EXIT=true		#When true, prints non-zero exit codes into prompt (zero exit codes are not shown)
 
 # Example prompts:
 # bsd: user@host:~/storage/git[git-branch]%

prompt

@@ -36,3 +36,9 @@ fi
 ### UNUSED ### New style with primary-coloured %/#
 #PROMPT="%B%{$fg[$COLOR_USER]%}%n@%m%b%{$reset_color%}:%{$fg[$COLOR_PWD]%}%~%{$fg[$COLOR_VCS]%}%B\$vcs_info_msg_0_%b%{$fg[$COLOR_PWD]%}%B%{$fg[$COLOR]%}%# %{$reset_color%}"
 
+# Print previous exit code only if exit code was non-zero
+if [ "$SHOW_NZ_EXIT" = "true" ]
+then
+  PROMPT="%(?..%?:)${PROMPT}"
+fi
+