diff --git a/plugins/pycv/regtest/pycvcomm/rt-MDinformations/config b/plugins/pycv/regtest/pycvcomm/rt-MDinformations/config
index af185de1f2..293f9280a2 100644
--- a/plugins/pycv/regtest/pycvcomm/rt-MDinformations/config
+++ b/plugins/pycv/regtest/pycvcomm/rt-MDinformations/config
@@ -7,7 +7,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvcomm/rt-PBC-getBox/config b/plugins/pycv/regtest/pycvcomm/rt-PBC-getBox/config
index bca39af1e7..9cca9530cc 100644
--- a/plugins/pycv/regtest/pycvcomm/rt-PBC-getBox/config
+++ b/plugins/pycv/regtest/pycvcomm/rt-PBC-getBox/config
@@ -7,7 +7,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvcomm/rt-PBC-getInvBox/config b/plugins/pycv/regtest/pycvcomm/rt-PBC-getInvBox/config
index bca39af1e7..9cca9530cc 100644
--- a/plugins/pycv/regtest/pycvcomm/rt-PBC-getInvBox/config
+++ b/plugins/pycv/regtest/pycvcomm/rt-PBC-getInvBox/config
@@ -7,7 +7,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvcomm/rt-PBCs/config b/plugins/pycv/regtest/pycvcomm/rt-PBCs/config
index bca39af1e7..9cca9530cc 100644
--- a/plugins/pycv/regtest/pycvcomm/rt-PBCs/config
+++ b/plugins/pycv/regtest/pycvcomm/rt-PBCs/config
@@ -7,7 +7,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvcomm/rt-absoluteIndexes/config b/plugins/pycv/regtest/pycvcomm/rt-absoluteIndexes/config
index bca39af1e7..9cca9530cc 100644
--- a/plugins/pycv/regtest/pycvcomm/rt-absoluteIndexes/config
+++ b/plugins/pycv/regtest/pycvcomm/rt-absoluteIndexes/config
@@ -7,7 +7,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvcomm/rt-autoFunctions/config b/plugins/pycv/regtest/pycvcomm/rt-autoFunctions/config
index bca39af1e7..9cca9530cc 100644
--- a/plugins/pycv/regtest/pycvcomm/rt-autoFunctions/config
+++ b/plugins/pycv/regtest/pycvcomm/rt-autoFunctions/config
@@ -7,7 +7,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvcomm/rt-doc/config b/plugins/pycv/regtest/pycvcomm/rt-doc/config
index bca39af1e7..9cca9530cc 100644
--- a/plugins/pycv/regtest/pycvcomm/rt-doc/config
+++ b/plugins/pycv/regtest/pycvcomm/rt-doc/config
@@ -7,7 +7,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvcomm/rt-doc/config.reference b/plugins/pycv/regtest/pycvcomm/rt-doc/config.reference
index bca39af1e7..9cca9530cc 100644
--- a/plugins/pycv/regtest/pycvcomm/rt-doc/config.reference
+++ b/plugins/pycv/regtest/pycvcomm/rt-doc/config.reference
@@ -7,7 +7,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvcomm/rt-getPosition/config b/plugins/pycv/regtest/pycvcomm/rt-getPosition/config
index bca39af1e7..9cca9530cc 100644
--- a/plugins/pycv/regtest/pycvcomm/rt-getPosition/config
+++ b/plugins/pycv/regtest/pycvcomm/rt-getPosition/config
@@ -7,7 +7,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvcomm/rt-getPositionNL/config b/plugins/pycv/regtest/pycvcomm/rt-getPositionNL/config
index bca39af1e7..9cca9530cc 100644
--- a/plugins/pycv/regtest/pycvcomm/rt-getPositionNL/config
+++ b/plugins/pycv/regtest/pycvcomm/rt-getPositionNL/config
@@ -7,7 +7,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvcomm/rt-getPositionNLPair/config b/plugins/pycv/regtest/pycvcomm/rt-getPositionNLPair/config
index bca39af1e7..9cca9530cc 100644
--- a/plugins/pycv/regtest/pycvcomm/rt-getPositionNLPair/config
+++ b/plugins/pycv/regtest/pycvcomm/rt-getPositionNLPair/config
@@ -7,7 +7,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvcomm/rt-getPositions/config b/plugins/pycv/regtest/pycvcomm/rt-getPositions/config
index bca39af1e7..9cca9530cc 100644
--- a/plugins/pycv/regtest/pycvcomm/rt-getPositions/config
+++ b/plugins/pycv/regtest/pycvcomm/rt-getPositions/config
@@ -7,7 +7,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvcomm/rt-makeWhole/config b/plugins/pycv/regtest/pycvcomm/rt-makeWhole/config
index bca39af1e7..9cca9530cc 100644
--- a/plugins/pycv/regtest/pycvcomm/rt-makeWhole/config
+++ b/plugins/pycv/regtest/pycvcomm/rt-makeWhole/config
@@ -7,7 +7,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvcomm/rt-massesAndCharges/config b/plugins/pycv/regtest/pycvcomm/rt-massesAndCharges/config
index af185de1f2..293f9280a2 100644
--- a/plugins/pycv/regtest/pycvcomm/rt-massesAndCharges/config
+++ b/plugins/pycv/regtest/pycvcomm/rt-massesAndCharges/config
@@ -7,7 +7,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvcomm/rt-massesAndChargesArray/config b/plugins/pycv/regtest/pycvcomm/rt-massesAndChargesArray/config
index af185de1f2..293f9280a2 100644
--- a/plugins/pycv/regtest/pycvcomm/rt-massesAndChargesArray/config
+++ b/plugins/pycv/regtest/pycvcomm/rt-massesAndChargesArray/config
@@ -7,7 +7,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvcomm/rt-multipleComponents/config b/plugins/pycv/regtest/pycvcomm/rt-multipleComponents/config
index bca39af1e7..9cca9530cc 100644
--- a/plugins/pycv/regtest/pycvcomm/rt-multipleComponents/config
+++ b/plugins/pycv/regtest/pycvcomm/rt-multipleComponents/config
@@ -7,7 +7,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvcomm/rt-multipleValuePeriodicity/config b/plugins/pycv/regtest/pycvcomm/rt-multipleValuePeriodicity/config
index bca39af1e7..9cca9530cc 100644
--- a/plugins/pycv/regtest/pycvcomm/rt-multipleValuePeriodicity/config
+++ b/plugins/pycv/regtest/pycvcomm/rt-multipleValuePeriodicity/config
@@ -7,7 +7,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvcomm/rt-multiplecalls/config b/plugins/pycv/regtest/pycvcomm/rt-multiplecalls/config
index dca9b502ca..e94ad8dbb3 100644
--- a/plugins/pycv/regtest/pycvcomm/rt-multiplecalls/config
+++ b/plugins/pycv/regtest/pycvcomm/rt-multiplecalls/config
@@ -7,7 +7,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvcomm/rt-newFrameNewAtom/config b/plugins/pycv/regtest/pycvcomm/rt-newFrameNewAtom/config
index bca39af1e7..9cca9530cc 100644
--- a/plugins/pycv/regtest/pycvcomm/rt-newFrameNewAtom/config
+++ b/plugins/pycv/regtest/pycvcomm/rt-newFrameNewAtom/config
@@ -7,7 +7,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvcomm/rt-newFrameNewAtomSTR/config b/plugins/pycv/regtest/pycvcomm/rt-newFrameNewAtomSTR/config
index bca39af1e7..9cca9530cc 100644
--- a/plugins/pycv/regtest/pycvcomm/rt-newFrameNewAtomSTR/config
+++ b/plugins/pycv/regtest/pycvcomm/rt-newFrameNewAtomSTR/config
@@ -7,7 +7,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvcomm/rt-persistentData/config b/plugins/pycv/regtest/pycvcomm/rt-persistentData/config
index a0ec704a92..18862d248b 100644
--- a/plugins/pycv/regtest/pycvcomm/rt-persistentData/config
+++ b/plugins/pycv/regtest/pycvcomm/rt-persistentData/config
@@ -10,7 +10,7 @@ plumed_regtest_before(){
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvcomm/rt-valuePeriodicity/config b/plugins/pycv/regtest/pycvcomm/rt-valuePeriodicity/config
index bca39af1e7..9cca9530cc 100644
--- a/plugins/pycv/regtest/pycvcomm/rt-valuePeriodicity/config
+++ b/plugins/pycv/regtest/pycvcomm/rt-valuePeriodicity/config
@@ -7,7 +7,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvfunc/rt-ArgsMethods/config b/plugins/pycv/regtest/pycvfunc/rt-ArgsMethods/config
index bca39af1e7..9cca9530cc 100644
--- a/plugins/pycv/regtest/pycvfunc/rt-ArgsMethods/config
+++ b/plugins/pycv/regtest/pycvfunc/rt-ArgsMethods/config
@@ -7,7 +7,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvfunc/rt-Components/config b/plugins/pycv/regtest/pycvfunc/rt-Components/config
index bca39af1e7..9cca9530cc 100644
--- a/plugins/pycv/regtest/pycvfunc/rt-Components/config
+++ b/plugins/pycv/regtest/pycvfunc/rt-Components/config
@@ -7,7 +7,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvfunc/rt-MDinformations/config b/plugins/pycv/regtest/pycvfunc/rt-MDinformations/config
index bca39af1e7..9cca9530cc 100644
--- a/plugins/pycv/regtest/pycvfunc/rt-MDinformations/config
+++ b/plugins/pycv/regtest/pycvfunc/rt-MDinformations/config
@@ -7,7 +7,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvfunc/rt-arguments/config b/plugins/pycv/regtest/pycvfunc/rt-arguments/config
index bca39af1e7..9cca9530cc 100644
--- a/plugins/pycv/regtest/pycvfunc/rt-arguments/config
+++ b/plugins/pycv/regtest/pycvfunc/rt-arguments/config
@@ -7,7 +7,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvfunc/rt-argumentsArray/config b/plugins/pycv/regtest/pycvfunc/rt-argumentsArray/config
index bca39af1e7..9cca9530cc 100644
--- a/plugins/pycv/regtest/pycvfunc/rt-argumentsArray/config
+++ b/plugins/pycv/regtest/pycvfunc/rt-argumentsArray/config
@@ -7,7 +7,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvfunc/rt-argumentsWithComponents/config b/plugins/pycv/regtest/pycvfunc/rt-argumentsWithComponents/config
index bca39af1e7..9cca9530cc 100644
--- a/plugins/pycv/regtest/pycvfunc/rt-argumentsWithComponents/config
+++ b/plugins/pycv/regtest/pycvfunc/rt-argumentsWithComponents/config
@@ -7,7 +7,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvfunc/rt-derivative/config b/plugins/pycv/regtest/pycvfunc/rt-derivative/config
index a9b93b35ca..75fa9a51a6 100644
--- a/plugins/pycv/regtest/pycvfunc/rt-derivative/config
+++ b/plugins/pycv/regtest/pycvfunc/rt-derivative/config
@@ -15,7 +15,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvfunc/rt-doc/config b/plugins/pycv/regtest/pycvfunc/rt-doc/config
index bca39af1e7..9cca9530cc 100644
--- a/plugins/pycv/regtest/pycvfunc/rt-doc/config
+++ b/plugins/pycv/regtest/pycvfunc/rt-doc/config
@@ -7,7 +7,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvfunc/rt-doc/config.reference b/plugins/pycv/regtest/pycvfunc/rt-doc/config.reference
index bca39af1e7..9cca9530cc 100644
--- a/plugins/pycv/regtest/pycvfunc/rt-doc/config.reference
+++ b/plugins/pycv/regtest/pycvfunc/rt-doc/config.reference
@@ -7,7 +7,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {
diff --git a/plugins/pycv/regtest/pycvfunc/rt-withPYCV/config b/plugins/pycv/regtest/pycvfunc/rt-withPYCV/config
index bca39af1e7..9cca9530cc 100644
--- a/plugins/pycv/regtest/pycvfunc/rt-withPYCV/config
+++ b/plugins/pycv/regtest/pycvfunc/rt-withPYCV/config
@@ -7,7 +7,7 @@ plumed_regtest_before() {
         PLUMED_PYTHON_BIN=python
     fi
     pycvpath=$($PLUMED_PYTHON_BIN -m pycv)
-    sed -i "s%@pycvpath@%${pycvpath}%g" plumed.dat
+    sed -i.bak "s%@pycvpath@%${pycvpath}%g" plumed.dat
 }
 
 plumed_custom_skip() {