files: backup file collisions

When a configuration file would be written to an existing file, rather
than failing switch (and having the user have to move or delete those
files), move the files automatically to a new path.

Closes #585

1 files changed, 5 insertions, 1 deletions

diff --git a/home-manager/home-manager b/home-manager/home-manager
index 85feaae400d..b6ea92edb9e 100644
--- a/home-manager/home-manager
+++ b/home-manager/home-manager
@@ -416,6 +416,7 @@ function doHelp() {
     echo "  -A ATTRIBUTE Optional attribute that selects a configuration"
     echo "               expression in the configuration file."
     echo "  -I PATH      Add a path to the Nix expression search path."
+    echo "  -b EXT       Move existing files to new path rather than fail."
     echo "  -v           Verbose output"
     echo "  -n           Do a dry run, only prints what actions would be taken"
     echo "  -h           Print this help"
@@ -460,7 +461,7 @@ for arg in "$@"; do
     fi
 done
 
-while getopts 2f:I:A:vnh opt; do
+while getopts 2f:I:A:b:vnh opt; do
     case $opt in
         2)
             USE_NIX2_COMMAND=1
@@ -474,6 +475,9 @@ while getopts 2f:I:A:vnh opt; do
         A)
             HOME_MANAGER_CONFIG_ATTRIBUTE="$OPTARG"
             ;;
+        b)
+            export HOME_MANAGER_BACKUP_EXT="$OPTARG"
+            ;;
         v)
             export VERBOSE=1
             ;;