Add $FZF_DEFAULT_OPTS_FILE

For those who prefer to manage default options in a file.
If the file is not found, fzf will exit with an error.

We're not setting a default value for it because:

1. it's hard to find a default value that can be universally agreed upon
2. to avoid fzf having to check for the existence of the file even when it's not used

README.md

@@ -311,6 +311,10 @@ or `py`.
 - `FZF_DEFAULT_OPTS`
     - Default options
     - e.g. `export FZF_DEFAULT_OPTS="--layout=reverse --inline-info"`
+- `FZF_DEFAULT_OPTS_FILE`
+    - If you prefer to manage default options in a file, set this variable to
+      point to the location of the file
+    - e.g. `export FZF_DEFAULT_OPTS_FILE=~/.fzfrc`
 
 ### Options
 

man/man1/fzf.1

@@ -867,6 +867,9 @@ this case make sure that the command is POSIX-compliant.
 .B FZF_DEFAULT_OPTS
 Default options. e.g. \fBexport FZF_DEFAULT_OPTS="--extended --cycle"\fR
 .TP
+.B FZF_DEFAULT_OPTS_FILE
+The location of the file that contains the default options. e.g. \fBexport FZF_DEFAULT_OPTS_FILE=~/.fzfrc\fR
+.TP
 .B FZF_API_KEY
 Can be used to require an API key when using \fB--listen\fR option. If not set,
 no authentication will be required by the server. You can set this value if

src/options.go

@@ -421,8 +421,10 @@ func help(code int) {
 	os.Exit(code)
 }
 
+var errorContext = ""
+
 func errorExit(msg string) {
-	os.Stderr.WriteString(msg + "\n")
+	os.Stderr.WriteString(errorContext + msg + "\n")
 	os.Exit(exitError)
 }
 
@@ -2167,13 +2169,36 @@ func ParseOptions() *Options {
 		}
 	}
 
-	// Options from Env var
-	words, _ := shellwords.Parse(os.Getenv("FZF_DEFAULT_OPTS"))
+	// 1. Options from $FZF_DEFAULT_OPTS_FILE
+	if path := os.Getenv("FZF_DEFAULT_OPTS_FILE"); path != "" {
+		bytes, err := os.ReadFile(path)
+		if err != nil {
+			errorContext = "$FZF_DEFAULT_OPTS_FILE: "
+			errorExit(err.Error())
+		}
+
+		words, parseErr := shellwords.Parse(string(bytes))
+		if parseErr != nil {
+			errorContext = path + ": "
+			errorExit(parseErr.Error())
+		}
+		if len(words) > 0 {
+			parseOptions(opts, words)
+		}
+	}
+
+	// 2. Options from $FZF_DEFAULT_OPTS string
+	words, parseErr := shellwords.Parse(os.Getenv("FZF_DEFAULT_OPTS"))
+	errorContext = "$FZF_DEFAULT_OPTS: "
+	if parseErr != nil {
+		errorExit(parseErr.Error())
+	}
 	if len(words) > 0 {
 		parseOptions(opts, words)
 	}
 
-	// Options from command-line arguments
+	// 3. Options from command-line arguments
+	errorContext = ""
 	parseOptions(opts, os.Args[1:])
 
 	postProcessOptions(opts)