git-diff with stdin

Say you want to diff a local file with the contents of stdin.

Git has built-in support for that. A --no-index (used to compare two non-git things).

Example:

cat << EOF | git --no-pager diff --no-index -- - cf/types.go
package main

// these changes are from stdin
type DataRow struct {
    stackName  string
    awsProfile string
    awsRegion  string
    template   string
    local      int
    tag        *string
    drifted    bool
    err        error
}
EOF

Output:

diff --git a/- b/cf/types.go
index 0000000..2857c53 100644
--- a/-
+++ b/cf/types.go
@@ -1,13 +1,14 @@
 package main

-// these changes are from stdin
 type DataRow struct {
        stackName  string
        awsProfile string
        awsRegion  string
        template   string
-       local      int
+       local      string
        tag        *string
+       fetching   bool
+       fetched    bool
        drifted    bool
        err        error
 }