Implement source:destination as argument

Author: mblaschke

README.md

@@ -41,6 +41,15 @@ Application Options:
   -h, --help                                    show this help message
 ```
 
+Files must be specified as arguments and will be overwritten after parsing. If you want an alternative location for
+saving the file the argument can be specified as `source:destination`, eg.
+`go-replace -s foobar -r barfoo daemon.conf.tmpl:daemon.conf`.
+
+If `--path` (with or without `--path-pattern` or `--path-regex`) the files inside path are used as source and will
+be overwritten. If `daemon.conf.tmpl` should be written as `daemon.conf` the option `--output-strip-ext=.tmpl` will do
+this based on the source file name.
+
+
 | Mode       | Description                                                                                                                                                    |
 |:-----------|:---------------------------------------------------------------------------------------------------------------------------------------------------------------|
 | replace    | Replace search term inside one line with replacement.                                                                                                          |
@@ -75,7 +84,7 @@ Process file with:
 ```bash
 export SERVERNAME=www.foobar.example
 export DOCUMENTROOT=/var/www/foobar.example/
-go-replace --mode=template --output-strip-ext=.tmpl daemon.conf.tmpl
+go-replace --mode=template daemon.conf.tmpl:daemon.conf
 ```
 
 Reuslt file `daemon.conf`:

goreplace.go

@@ -586,9 +586,17 @@ func buildFileitems(args []string) ([]fileitem) {
         file := fileitem{filepath, filepath}
 
         if opts.Output != "" {
+            // use specific output
             file.Output = opts.Output
         } else if opts.OutputStripFileExt != "" {
+            // remove file ext from saving destination
             file.Output = strings.TrimSuffix(file.Output, opts.OutputStripFileExt)
+        } else if strings.Contains(filepath, ":") {
+            // argument like "source:destination"
+            pair := strings.Split(filepath, ":")
+
+            file.Path = pair[0]
+            file.Output = pair[1]
         }
 
         fileitems = append(fileitems, file)

tests/main.test

@@ -507,3 +507,18 @@ Testing with --output but multiple arguments:
 
   [1]
 
+Testing with source:dest:
+
+  $ cat > test.txt <<EOF
+  > this is a testline
+  > this is the second line
+  > this is the third foobar line
+  > this is the last line
+  > EOF
+  $ goreplace -s foobar -r ___xxx test.txt:test.output
+  $ cat test.output
+  this is a testline
+  this is the second line
+  this is the third ___xxx line
+  this is the last line
+