diff --git a/master_changes.md b/master_changes.md
index 65e46b140c3..4dbf1226680 100644
--- a/master_changes.md
+++ b/master_changes.md
@@ -106,6 +106,7 @@ users)
   * Move local-cache into archive-field-checks test [#5560 @rjbou]
 
 ### Engine
+  * Reimplement `sed-cmd` command regexp, to handle prefixed commands with path not only in subprocess, but anywere in output [#5657 @rjbou]
 
 ## Github Actions
   * Add coreutils install for cheksum validation tests [#5560 @rjbou]
diff --git a/tests/reftests/assume-built.test b/tests/reftests/assume-built.test
index 81f4fb9f0b9..91cfc4379a7 100644
--- a/tests/reftests/assume-built.test
+++ b/tests/reftests/assume-built.test
@@ -33,14 +33,14 @@ The following actions will be performed:
 Processing  1/3: [ongoing.dev: git]
 -> retrieved ongoing.dev  (no changes)
 Processing  2/3: [ongoing: test ongoing.txt]
-test "-f" "ongoing.txt" (CWD=${BASEDIR}/OPAM/assume-built/.opam-switch/build/ongoing.dev)
++ test "-f" "ongoing.txt" (CWD=${BASEDIR}/OPAM/assume-built/.opam-switch/build/ongoing.dev)
 Processing  2/3: [ongoing: sh cat ongoing.txt > out]
-sh "-c" "cat ongoing.txt > out" (CWD=${BASEDIR}/OPAM/assume-built/.opam-switch/build/ongoing.dev)
++ sh "-c" "cat ongoing.txt > out" (CWD=${BASEDIR}/OPAM/assume-built/.opam-switch/build/ongoing.dev)
 -> compiled  ongoing.dev
 Processing  3/3: [ongoing: test out]
-test "-f" "out" (CWD=${BASEDIR}/OPAM/assume-built/.opam-switch/build/ongoing.dev)
++ test "-f" "out" (CWD=${BASEDIR}/OPAM/assume-built/.opam-switch/build/ongoing.dev)
 Processing  3/3: [ongoing: touch installed]
-touch "installed" (CWD=${BASEDIR}/OPAM/assume-built/.opam-switch/build/ongoing.dev)
++ touch "installed" (CWD=${BASEDIR}/OPAM/assume-built/.opam-switch/build/ongoing.dev)
 -> installed ongoing.dev
 Done.
 ### opam remove ongoing
@@ -67,7 +67,7 @@ The following actions will be performed:
 Processing  1/3: [ongoing.dev: git]
 -> retrieved ongoing.dev  (no changes)
 Processing  3/3: [ongoing: test out]
-test "-f" "out" (CWD=${BASEDIR}/ongoing)
++ test "-f" "out" (CWD=${BASEDIR}/ongoing)
 [ERROR] The installation of ongoing failed at "test -f out".
 
 
@@ -97,9 +97,9 @@ The following actions will be performed:
 Processing  1/3: [ongoing.dev: git]
 -> retrieved ongoing.dev  (no changes)
 Processing  3/3: [ongoing: test out]
-test "-f" "out" (CWD=${BASEDIR}/ongoing)
++ test "-f" "out" (CWD=${BASEDIR}/ongoing)
 Processing  3/3: [ongoing: touch installed]
-touch "installed" (CWD=${BASEDIR}/ongoing)
++ touch "installed" (CWD=${BASEDIR}/ongoing)
 -> installed ongoing.dev
 Done.
 ### test -f ./ongoing/installed
@@ -160,9 +160,9 @@ The following actions will be performed:
 
 <><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
 Processing  2/2: [ongoing: test out2]
-test "-f" "out2" (CWD=${BASEDIR}/ongoing)
++ test "-f" "out2" (CWD=${BASEDIR}/ongoing)
 Processing  2/2: [ongoing: touch installed]
-touch "installed" (CWD=${BASEDIR}/ongoing)
++ touch "installed" (CWD=${BASEDIR}/ongoing)
 -> installed ongoing.dev
 Done.
 ### test -f ./ongoing/installed
diff --git a/tests/reftests/autopin.test b/tests/reftests/autopin.test
index 2f3c650f63e..7f6e3aba571 100644
--- a/tests/reftests/autopin.test
+++ b/tests/reftests/autopin.test
@@ -65,7 +65,7 @@ opam believes some required external dependencies are missing. opam can:
 
 [1/2/3/4] 1
 
-echo "some-depext"
++ echo "some-depext"
 - some-depext
 
 <><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -112,7 +112,7 @@ opam believes some required external dependencies are missing. opam can:
 
 [1/2/3/4] 1
 
-echo "some-depext"
++ echo "some-depext"
 - some-depext
 
 <><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -156,7 +156,7 @@ opam believes some required external dependencies are missing. opam can:
 
 [1/2/3/4] 1
 
-echo "some-depext"
++ echo "some-depext"
 - some-depext
 
 <><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -208,7 +208,7 @@ opam believes some required external dependencies are missing. opam can:
 
 [1/2/3/4] 1
 
-echo "some-depext"
++ echo "some-depext"
 - some-depext
 
 <><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
@@ -241,7 +241,7 @@ The following system packages will first need to be installed:
 
 <><> Handling external dependencies <><><><><><><><><><><><><><><><><><><><><><>
 
-echo "some-depext"
++ echo "some-depext"
 - some-depext
 ### opam remove foo-format | grep -v import
 [WARNING] Opam package foo-format.2.0 depends on the following system package that can no longer be found: some-depext
@@ -317,6 +317,6 @@ opam believes some required external dependencies are missing. opam can:
 
 [1/2/3/4] 1
 
-echo "some-depext"
++ echo "some-depext"
 - some-depext
 Nothing to do.
diff --git a/tests/reftests/depexts.test b/tests/reftests/depexts.test
index 22d47fbb9cc..71e3edd9b27 100644
--- a/tests/reftests/depexts.test
+++ b/tests/reftests/depexts.test
@@ -25,7 +25,7 @@ opam believes some required external dependencies are missing. opam can:
 
 [1/2/3/4] 1
 
-false 
++ false 
 [ERROR] System package install failed with exit code 1 at command:
             false
 [ERROR] These packages are still missing: depext-1
diff --git a/tests/reftests/inplace.test b/tests/reftests/inplace.test
index 600535c0c26..3f1877202e7 100644
--- a/tests/reftests/inplace.test
+++ b/tests/reftests/inplace.test
@@ -32,13 +32,13 @@ The following actions will be performed:
 Processing  1/3: [ongoing.dev: git]
 -> retrieved ongoing.dev  (no changes)
 Processing  2/3: [ongoing: test ongoing.txt]
-test "-f" "ongoing.txt" (CWD=${BASEDIR}/OPAM/inplace/.opam-switch/build/ongoing.dev)
++ test "-f" "ongoing.txt" (CWD=${BASEDIR}/OPAM/inplace/.opam-switch/build/ongoing.dev)
 Processing  2/3: [ongoing: cat ongoing.txt]
-cat "ongoing.txt" (CWD=${BASEDIR}/OPAM/inplace/.opam-switch/build/ongoing.dev)
++ cat "ongoing.txt" (CWD=${BASEDIR}/OPAM/inplace/.opam-switch/build/ongoing.dev)
 - versionned
 -> compiled  ongoing.dev
 Processing  3/3: [ongoing: touch installed]
-touch "installed" (CWD=${BASEDIR}/OPAM/inplace/.opam-switch/build/ongoing.dev)
++ touch "installed" (CWD=${BASEDIR}/OPAM/inplace/.opam-switch/build/ongoing.dev)
 -> installed ongoing.dev
 Done.
 ### test -f ./ongoing/installed
@@ -65,13 +65,13 @@ The following actions will be performed:
 Processing  1/3: [ongoing.dev: git]
 -> retrieved ongoing.dev  (no changes)
 Processing  2/3: [ongoing: test ongoing.txt]
-test "-f" "ongoing.txt" (CWD=${BASEDIR}/ongoing)
++ test "-f" "ongoing.txt" (CWD=${BASEDIR}/ongoing)
 Processing  2/3: [ongoing: cat ongoing.txt]
-cat "ongoing.txt" (CWD=${BASEDIR}/ongoing)
++ cat "ongoing.txt" (CWD=${BASEDIR}/ongoing)
 - versionned
 -> compiled  ongoing.dev
 Processing  3/3: [ongoing: touch installed]
-touch "installed" (CWD=${BASEDIR}/ongoing)
++ touch "installed" (CWD=${BASEDIR}/ongoing)
 -> installed ongoing.dev
 Done.
 ### test -f ./ongoing/installed
@@ -102,13 +102,13 @@ The following actions will be performed:
 
 <><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
 Processing  1/2: [ongoing: test newfile.txt]
-test "-f" "newfile.txt" (CWD=${BASEDIR}/ongoing)
++ test "-f" "newfile.txt" (CWD=${BASEDIR}/ongoing)
 Processing  1/2: [ongoing: cat newfile.txt]
-cat "newfile.txt" (CWD=${BASEDIR}/ongoing)
++ cat "newfile.txt" (CWD=${BASEDIR}/ongoing)
 - new!
 -> compiled  ongoing.dev
 Processing  2/2: [ongoing: touch installed]
-touch "installed" (CWD=${BASEDIR}/ongoing)
++ touch "installed" (CWD=${BASEDIR}/ongoing)
 -> installed ongoing.dev
 Done.
 ### test -f ./ongoing/installed
diff --git a/tests/reftests/parallel.test b/tests/reftests/parallel.test
index e036f961b2b..19aea09517c 100644
--- a/tests/reftests/parallel.test
+++ b/tests/reftests/parallel.test
@@ -42,23 +42,23 @@ The following actions will be performed:
   - install qux 1
 
 <><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
-sh "sleep.sh" "bar" (CWD=${BASEDIR}/OPAM/parallel/.opam-switch/build/bar.1)
-- woke up bar
 -> compiled  bar.1
 -> installed bar.1
-sh "sleep.sh" "baz" (CWD=${BASEDIR}/OPAM/parallel/.opam-switch/build/baz.1)
-- woke up baz
++ sh "sleep.sh" "bar" (CWD=${BASEDIR}/OPAM/parallel/.opam-switch/build/bar.1)
+- woke up bar
 -> compiled  baz.1
 -> installed baz.1
-sh "sleep.sh" "foo" (CWD=${BASEDIR}/OPAM/parallel/.opam-switch/build/foo.1)
++ sh "sleep.sh" "baz" (CWD=${BASEDIR}/OPAM/parallel/.opam-switch/build/baz.1)
+- woke up baz
 -> compiled  foo.1
 -> installed foo.1
-sh "sleep.sh" "qux" (CWD=${BASEDIR}/OPAM/parallel/.opam-switch/build/qux.1)
++ sh "sleep.sh" "foo" (CWD=${BASEDIR}/OPAM/parallel/.opam-switch/build/foo.1)
 -> compiled  qux.1
 -> installed qux.1
-sh "shout.sh" (CWD=${BASEDIR}/OPAM/parallel/.opam-switch/build/top.1)
++ sh "sleep.sh" "qux" (CWD=${BASEDIR}/OPAM/parallel/.opam-switch/build/qux.1)
 -> compiled  top.1
-sh "shout.sh" "top" (CWD=${BASEDIR}/OPAM/parallel/.opam-switch/build/top.1)
++ sh "shout.sh" (CWD=${BASEDIR}/OPAM/parallel/.opam-switch/build/top.1)
++ sh "shout.sh" "top" (CWD=${BASEDIR}/OPAM/parallel/.opam-switch/build/top.1)
 - finally installed top
 -> installed top.1
 Done.
diff --git a/tests/reftests/reinstall.test b/tests/reftests/reinstall.test
index 6bb760e4d1f..b346792407d 100644
--- a/tests/reftests/reinstall.test
+++ b/tests/reftests/reinstall.test
@@ -46,14 +46,14 @@ Nothing to do.
 opam-version: "2.0"
 build: ["opam" "var" "switch"]
 depends: ["b" {= version}]
-### opam upgrade -y --verbose | '^\+ .+ "build"' -> '+' | '^\+ .+opam(\.exe)? ' -> '+ "opam" '
+### opam upgrade -y --verbose | sed-cmd opam
 The following actions will be performed:
 === recompile 1 package
   - recompile a 1 [upstream or system changes]
 
 <><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
 Processing  2/4: [a: opam var]
-+ "opam" "var" "switch" (CWD=${BASEDIR}/OPAM/default/.opam-switch/build/a.1)
++ opam "var" "switch" (CWD=${BASEDIR}/OPAM/default/.opam-switch/build/a.1)
 - default
 -> compiled  a.1
 -> removed   a.1
diff --git a/tests/reftests/repository.test b/tests/reftests/repository.test
index cb248b62092..3e087df0333 100644
--- a/tests/reftests/repository.test
+++ b/tests/reftests/repository.test
@@ -6,15 +6,15 @@ build: ["test" "-f" "bar"]
 some content
 ### : Internal repository storage as archive or plain directory :
 ### opam switch create tarring --empty
-### opam update -vv | grep '^\+' | sed-cmd diff | '.*(/|\\)patch(\.exe)?"?.*"' -> 'patch'
-diff "-ruaN" "default" "default.new" (CWD=${BASEDIR}/OPAM/repo)
-patch (CWD=${BASEDIR}/OPAM/repo/default)
+### opam update -vv | grep '^\+' | sed-cmd diff | sed-cmd patch | 'patch-[^"]+' -> 'patch'
++ diff "-ruaN" "default" "default.new" (CWD=${BASEDIR}/OPAM/repo)
++ patch "-p1" "-i" "${BASEDIR}/OPAM/log/patch" (CWD=${BASEDIR}/OPAM/repo/default)
 ### ls $OPAMROOT/repo | grep -v "cache"
 default
 lock
 repos-config
 ### opam install foo.1 -vv | grep '^\+' | sed-cmd test
-test "-f" "bar" (CWD=${BASEDIR}/OPAM/tarring/.opam-switch/build/foo.1)
++ test "-f" "bar" (CWD=${BASEDIR}/OPAM/tarring/.opam-switch/build/foo.1)
 ### opam repository add plain ./REPO --this-switch
 [plain] Initialised
 ### OPAMREPOSITORYTARRING=1
@@ -24,18 +24,18 @@ opam-version: "2.0"
 build: ["test" "-f" "baz"]
 ### <REPO/packages/foo/foo.2/files/baz>
 some content
-### opam update default -vv | grep '^\+' | '.*tar(\.exe)?"? "xfz" ".*(/|\\)OPAM(/|\\)repo(/|\\)default\.tar\.gz" "-C" ".*"' -> 'tar xfz OPAM/repo/default.tar.gz -C TMPDIR' | '.*tar(\.exe)?"? "cfz" ".*(/|\\)OPAM(/|\\)repo(/|\\)default\.tar\.gz\.tmp" "-C" ".*" "default"' -> 'tar cfz OPAM/repo/default.tar.gz.tmp -C TMPDIR default' | sed-cmd diff | '.*(/|\\)patch(\.exe)?"?.*"' -> 'patch'
-diff "-ruaN" "default" "default.new" (CWD=${BASEDIR}/OPAM/repo)
-patch (CWD=${BASEDIR}/OPAM/repo/default)
-tar cfz OPAM/repo/default.tar.gz.tmp -C TMPDIR default
+### opam update default -vv | grep '^\+' | sed-cmd tar | sed-cmd diff | sed-cmd patch | 'patch-[^"]+' -> 'patch'
++ diff "-ruaN" "default" "default.new" (CWD=${BASEDIR}/OPAM/repo)
++ patch "-p1" "-i" "${BASEDIR}/OPAM/log/patch" (CWD=${BASEDIR}/OPAM/repo/default)
++ tar "cfz" "${BASEDIR}/OPAM/repo/default.tar.gz.tmp" "-C" "${BASEDIR}/OPAM/repo" "default"
 ### ls $OPAMROOT/repo | grep -v "cache"
 default.tar.gz
 lock
 plain
 repos-config
-### opam install foo.2 -vv | grep '^\+' | sed-cmd test | '.*tar(\.exe)?"? "xfz" ".*(/|\\)OPAM(/|\\)repo(/|\\)default\.tar\.gz" "-C" ".*"' -> 'tar xfz OPAM/repo/default.tar.gz -C TMPDIR'
-tar xfz OPAM/repo/default.tar.gz -C TMPDIR
-test "-f" "baz" (CWD=${BASEDIR}/OPAM/tarring/.opam-switch/build/foo.2)
+### opam install foo.2 -vv | grep '^\+' | sed-cmd test | sed-cmd tar
++ tar "xfz" "${BASEDIR}/OPAM/repo/default.tar.gz" "-C" "${OPAMTMP}"
++ test "-f" "baz" (CWD=${BASEDIR}/OPAM/tarring/.opam-switch/build/foo.2)
 ### opam repository remove default --all
 ### : Add tarred repo (tarred)
 ### <REPO/packages/foo/foo.3/opam>
@@ -51,9 +51,9 @@ lock
 plain
 repos-config
 tarred.tar.gz
-### opam install foo.3 -vv | grep '^\+' | sed-cmd test | '.*tar(\.exe)?"? "xfz" ".*(/|\\)OPAM(/|\\)repo(/|\\)tarred\.tar\.gz" "-C" ".*"' -> 'tar xfz OPAM/repo/tarred.tar.gz -C TMPDIR'
-tar xfz OPAM/repo/tarred.tar.gz -C TMPDIR
-test "-f" "baz" (CWD=${BASEDIR}/OPAM/tarring/.opam-switch/build/foo.3)
+### opam install foo.3 -vv | grep '^\+' | sed-cmd test | sed-cmd tar
++ tar "xfz" "${BASEDIR}/OPAM/repo/tarred.tar.gz" "-C" "${OPAMTMP}"
++ test "-f" "baz" (CWD=${BASEDIR}/OPAM/tarring/.opam-switch/build/foo.3)
 ### opam repository remove plain --all
 ### : Update tarred repo (tarred)
 ### <REPO/packages/foo/foo.4/opam>
@@ -61,14 +61,14 @@ opam-version: "2.0"
 build: ["test" "-f" "baz"]
 ### <REPO/packages/foo/foo.4/files/baz>
 some content
-### opam update -vv | grep '^\+' | '.*tar(\.exe)?"? "xfz" ".*(/|\\)OPAM(/|\\)repo(/|\\)tarred\.tar\.gz" "-C" ".*"' -> 'tar xfz OPAM/repo/tarred.tar.gz -C TMPDIR' | '.*tar(\.exe)?"? "cfz" ".*(/|\\)OPAM(/|\\)repo(/|\\)tarred\.tar\.gz\.tmp" "-C" ".*" "tarred"' -> 'tar cfz OPAM/repo/tarred.tar.gz.tmp -C TMPDIR tarred' | sed-cmd diff | '.*(/|\\)patch(\.exe)?"?.*"' -> 'patch'
-tar xfz OPAM/repo/tarred.tar.gz -C TMPDIR
-diff "-ruaN" "tarred" "tarred.new" (CWD=${OPAMTMP})
-patch (CWD=${OPAMTMP}/tarred)
-tar cfz OPAM/repo/tarred.tar.gz.tmp -C TMPDIR tarred
-### opam install foo.4 -vv | grep '^\+' | sed-cmd test | '.*tar(\.exe)?"? "xfz" ".*(/|\\)OPAM(/|\\)repo(/|\\)tarred\.tar\.gz" "-C" ".*"' -> 'tar xfz OPAM/repo/tarred.tar.gz -C TMPDIR'
-tar xfz OPAM/repo/tarred.tar.gz -C TMPDIR
-test "-f" "baz" (CWD=${BASEDIR}/OPAM/tarring/.opam-switch/build/foo.4)
+### opam update -vv | grep '^\+' | sed-cmd tar | sed-cmd diff | sed-cmd patch | 'patch-[^"]+' -> 'patch'
++ tar "xfz" "${BASEDIR}/OPAM/repo/tarred.tar.gz" "-C" "${OPAMTMP}"
++ diff "-ruaN" "tarred" "tarred.new" (CWD=${OPAMTMP})
++ patch "-p1" "-i" "${BASEDIR}/OPAM/log/patch" (CWD=${OPAMTMP}/tarred)
++ tar "cfz" "${BASEDIR}/OPAM/repo/tarred.tar.gz.tmp" "-C" "${OPAMTMP}" "tarred"
+### opam install foo.4 -vv | grep '^\+' | sed-cmd test | sed-cmd tar
++ tar "xfz" "${BASEDIR}/OPAM/repo/tarred.tar.gz" "-C" "${OPAMTMP}"
++ test "-f" "baz" (CWD=${BASEDIR}/OPAM/tarring/.opam-switch/build/foo.4)
 ### mkdir tarred-ext
 ### tar xf OPAM/repo/tarred.tar.gz
 ### diff -ru ./tarred REPO
@@ -83,12 +83,12 @@ opam-version: "2.0"
 build: ["test" "-f" "quux"]
 ### <REPO/packages/foo/foo.5/files/quux>
 some content
-### opam update -vv | grep '^\+' | '.*tar(\.exe)?"? "xfz" ".*(/|\\)OPAM(/|\\)repo(/|\\)tarred\.tar\.gz" "-C" ".*"' -> 'tar xfz OPAM/repo/tarred.tar.gz -C TMPDIR' | sed-cmd diff | '.*(/|\\)patch(\.exe)?"?.*"' -> 'patch'
-tar xfz OPAM/repo/tarred.tar.gz -C TMPDIR
-diff "-ruaN" "tarred" "tarred.new" (CWD=${OPAMTMP})
-patch (CWD=${OPAMTMP}/tarred)
-### opam install foo.5 -vv | grep '^\+' | sed-cmd test | '.*tar(\.exe)?"? "xfz" ".*(/|\\)OPAM(/|\\)repo(/|\\)tarred\.tar\.gz" "-C" ".*"' -> 'tar xfz OPAM/repo/tarred.tar.gz -C TMPDIR'
-test "-f" "quux" (CWD=${BASEDIR}/OPAM/tarring/.opam-switch/build/foo.5)
+### opam update -vv | grep '^\+' | sed-cmd tar | sed-cmd diff | sed-cmd patch | 'patch-[^"]+' -> 'patch'
++ tar "xfz" "${BASEDIR}/OPAM/repo/tarred.tar.gz" "-C" "${OPAMTMP}"
++ diff "-ruaN" "tarred" "tarred.new" (CWD=${OPAMTMP})
++ patch "-p1" "-i" "${BASEDIR}/OPAM/log/patch" (CWD=${OPAMTMP}/tarred)
+### opam install foo.5 -vv | grep '^\+' | sed-cmd test
++ test "-f" "quux" (CWD=${BASEDIR}/OPAM/tarring/.opam-switch/build/foo.5)
 ### ls $OPAMROOT/repo | grep -v "cache"
 lock
 repos-config
@@ -294,7 +294,7 @@ opam-version: "2.0"
 # Name # Installed # Synopsis
 first  --
 ### ::: rsync - git :::
-### opam repository set-url oper git+file://$BASEDIR/OPER4 | ': ".*git(.exe)?' -> ': "git'
+### opam repository set-url oper git+file://$BASEDIR/OPER4 | sed-cmd git
 [ERROR] Could not update repository "oper": "git fetch -q" exited with code 128
 [ERROR] Fetching repository oper with git+file://${BASEDIR}/OPER4 fails, reverting to file://${BASEDIR}/OPER
 # Return code 40 #
@@ -302,7 +302,7 @@ first  --
 # Packages matching: from-repository(oper) & available
 # Name # Installed # Synopsis
 first  --
-### opam repository set-url oper git+file://./OPER3#unknownbranch | ': ".*git(.exe)?' -> ': "git'
+### opam repository set-url oper git+file://./OPER3#unknownbranch | sed-cmd git
 [ERROR] Could not update repository "oper": "git fetch -q" exited with code 128
 [ERROR] Fetching repository oper with git+file://./OPER3#unknownbranch fails, reverting to file://${BASEDIR}/OPER
 # Return code 40 #
@@ -333,7 +333,7 @@ first  --
 # Name # Installed # Synopsis
 first  --
 ### ::: git - git :::
-### opam repository set-url oper git+file://$BASEDIR/OPER4 | ': ".*git(.exe)?' -> ': "git'
+### opam repository set-url oper git+file://$BASEDIR/OPER4 | sed-cmd git
 [ERROR] Could not update repository "oper": "git fetch -q" exited with code 128
 [ERROR] Fetching repository oper with git+file://${BASEDIR}/OPER4 fails, reverting to git+file://${BASEDIR}/OPER
 # Return code 40 #
@@ -341,7 +341,7 @@ first  --
 # Packages matching: from-repository(oper) & available
 # Name # Installed # Synopsis
 first  --
-### opam repository set-url oper git+file://./OPER3#unknownbranch | ': ".*git(.exe)?' -> ': "git'
+### opam repository set-url oper git+file://./OPER3#unknownbranch | sed-cmd git
 [ERROR] Could not update repository "oper": "git fetch -q" exited with code 128
 [ERROR] Fetching repository oper with git+file://./OPER3#unknownbranch fails, reverting to git+file://${BASEDIR}/OPER
 # Return code 40 #
@@ -460,7 +460,7 @@ opam-version: "2.0"
 # Name # Installed # Synopsis
 first  --
 ### :::: rsync - git ::::
-### opam repository set-url oper git+file://$BASEDIR/OPER4 | ': ".*git(.exe)?' -> ': "git'
+### opam repository set-url oper git+file://$BASEDIR/OPER4 | sed-cmd git
 [ERROR] Could not update repository "oper": "git fetch -q" exited with code 128
 [ERROR] Fetching repository oper with git+file://${BASEDIR}/OPER4 fails, reverting to file://${BASEDIR}/OPER
 # Return code 40 #
@@ -468,7 +468,7 @@ first  --
 # Packages matching: from-repository(oper) & available
 # Name # Installed # Synopsis
 first  --
-### opam repository set-url oper git+file://./OPER3#unknownbranch | ': ".*git(.exe)?' -> ': "git'
+### opam repository set-url oper git+file://./OPER3#unknownbranch | sed-cmd git
 [ERROR] Could not update repository "oper": "git fetch -q" exited with code 128
 [ERROR] Fetching repository oper with git+file://./OPER3#unknownbranch fails, reverting to file://${BASEDIR}/OPER
 # Return code 40 #
@@ -499,7 +499,7 @@ first  --
 # Name # Installed # Synopsis
 first  --
 ### :::: git - git ::::
-### opam repository set-url oper git+file://$BASEDIR/OPER4 | ': ".*git(.exe)?' -> ': "git'
+### opam repository set-url oper git+file://$BASEDIR/OPER4 | sed-cmd git
 [ERROR] Could not update repository "oper": "git fetch -q" exited with code 128
 [ERROR] Fetching repository oper with git+file://${BASEDIR}/OPER4 fails, reverting to git+file://${BASEDIR}/OPER
 # Return code 40 #
@@ -507,7 +507,7 @@ first  --
 # Packages matching: from-repository(oper) & available
 # Name # Installed # Synopsis
 first  --
-### opam repository set-url oper git+file://./OPER3#unknownbranch | ': ".*git(.exe)?' -> ': "git'
+### opam repository set-url oper git+file://./OPER3#unknownbranch | sed-cmd git
 [ERROR] Could not update repository "oper": "git fetch -q" exited with code 128
 [ERROR] Fetching repository oper with git+file://./OPER3#unknownbranch fails, reverting to git+file://${BASEDIR}/OPER
 # Return code 40 #
diff --git a/tests/reftests/run.ml b/tests/reftests/run.ml
index 30376afb6c7..03e2d2c4f09 100644
--- a/tests/reftests/run.ml
+++ b/tests/reftests/run.ml
@@ -421,18 +421,59 @@ module Parse = struct
           | "|" :: "unordered" :: r ->
             get_rewr (true, acc) r
           | "|" :: "sed-cmd" :: cmd :: r ->
-            let re =
+            let sandbox =
+              (* Sandbox prefix
+                 >[...] /tmp/build_592d92_dune/opam-reftest-2b89f9/OPAM/opam-init/hooks/sandbox.sh "build" "cmd" <
+                 >[...] ${BASEDIR}/opam-init/hooks/sandbox.sh "build" "cmd" <
+                 -->
+                 >[...] cmd <
+              *)
               seq [
-                Re.str "+ ";
-                rep any;
-                alt [ set "/\\\"" ];
+                alt [ char '/'; Re.str "${" ];
+                non_greedy @@ rep1 any; Re.str "sandbox.sh";
+                space;
+                char '"';
+                alt @@ List.map Re.str [ "build"; "install"; "remove" ];
+                char '"';
+                space;
+                char '"'; Re.str cmd; char '"';
+                space;
+              ]
+            in
+            let with_quote_set s = set ("\"'"^s) in
+            let opt_quoted r = [
+              seq @@ [ char '"'] @  r @ [ char '"'; rep1 space ];
+              seq @@ r @ [ rep1 space ];
+            ] in
+            let unix_prefix =
+              (* Unix & Mac command prefix
+                 >[...] /usr/bin/cmd <
+                 >[...] /usr/bin/cmd <
+                 -->
+                 >[...] cmd <
+              *)
+              opt_quoted @@ [
+                rep1 @@ seq [ char '/'; rep1 @@ diff any (with_quote_set "/ ") ];
+                char '/';
                 Re.str cmd;
-                opt @@ Re.str ".exe";
-                opt @@ char '"';
-                Re.str " "
               ]
-(*                 Printf.sprintf "+ .*(/|\\\\|\")%s(\\.exe)?\"? " cmd *)
-                in
+            in
+            let win_prefix =
+              (* Windows command prefix
+                 >[...] C:\Windows\system32\cmd.exe <
+                 >[...] C:\Windows\system32\cmd <
+                 >[...] C:\Windows\system 32\cmd <
+                 -->
+                 >[...] cmd <
+              *)
+              opt_quoted @@ [
+                alpha; char ':';
+                rep1 @@ seq [ char '\\'; rep1 @@ diff any (with_quote_set "\\") ];
+                char '\\';
+                Re.str cmd;
+                opt @@ Re.str ".exe";
+              ] in
+            let re = alt @@ sandbox :: unix_prefix @ win_prefix in
             let str = Printf.sprintf "%s " cmd in
             get_rewr (unordered, (re, Sed str) :: acc) r
           | ">$" :: output :: [] ->
diff --git a/tests/reftests/working-dir.test b/tests/reftests/working-dir.test
index 570dacbbde8..f432c25193f 100644
--- a/tests/reftests/working-dir.test
+++ b/tests/reftests/working-dir.test
@@ -51,9 +51,9 @@ The following actions will be performed:
 Processing  1/3: [ongoing.dev: git]
 -> retrieved ongoing.dev  (no changes)
 Processing  2/3: [ongoing: test ongoing.txt]
-test "-f" "ongoing.txt" (CWD=${BASEDIR}/OPAM/working-dir/.opam-switch/build/ongoing.dev)
++ test "-f" "ongoing.txt" (CWD=${BASEDIR}/OPAM/working-dir/.opam-switch/build/ongoing.dev)
 Processing  2/3: [ongoing: cat ongoing.txt]
-cat "ongoing.txt" (CWD=${BASEDIR}/OPAM/working-dir/.opam-switch/build/ongoing.dev)
++ cat "ongoing.txt" (CWD=${BASEDIR}/OPAM/working-dir/.opam-switch/build/ongoing.dev)
 - versionned
 -> compiled  ongoing.dev
 -> installed ongoing.dev
@@ -71,9 +71,9 @@ The following actions will be performed:
 
 <><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
 Processing  1/3: [ongoing: test newfile.txt]
-test "-f" "newfile.txt" (CWD=${BASEDIR}/OPAM/working-dir/.opam-switch/build/ongoing.dev)
++ test "-f" "newfile.txt" (CWD=${BASEDIR}/OPAM/working-dir/.opam-switch/build/ongoing.dev)
 Processing  1/3: [ongoing: cat newfile.txt]
-cat "newfile.txt" (CWD=${BASEDIR}/OPAM/working-dir/.opam-switch/build/ongoing.dev)
++ cat "newfile.txt" (CWD=${BASEDIR}/OPAM/working-dir/.opam-switch/build/ongoing.dev)
 - new!
 -> compiled  ongoing.dev
 -> removed   ongoing.dev
@@ -105,7 +105,7 @@ The following actions will be performed:
 Processing  1/3: [ongoing.dev: git]
 -> retrieved ongoing.dev  (no changes)
 Processing  2/3: [ongoing: test newfile.txt]
-test "-f" "newfile.txt" (CWD=${BASEDIR}/OPAM/working-dir/.opam-switch/build/ongoing.dev)
++ test "-f" "newfile.txt" (CWD=${BASEDIR}/OPAM/working-dir/.opam-switch/build/ongoing.dev)
 [ERROR] The compilation of ongoing.dev failed at "test -f newfile.txt".
 
 
@@ -130,9 +130,9 @@ The following actions will be performed:
 
 <><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
 Processing  1/2: [ongoing: test newfile.txt]
-test "-f" "newfile.txt" (CWD=${BASEDIR}/OPAM/working-dir/.opam-switch/build/ongoing.dev)
++ test "-f" "newfile.txt" (CWD=${BASEDIR}/OPAM/working-dir/.opam-switch/build/ongoing.dev)
 Processing  1/2: [ongoing: cat newfile.txt]
-cat "newfile.txt" (CWD=${BASEDIR}/OPAM/working-dir/.opam-switch/build/ongoing.dev)
++ cat "newfile.txt" (CWD=${BASEDIR}/OPAM/working-dir/.opam-switch/build/ongoing.dev)
 - new!
 -> compiled  ongoing.dev
 -> installed ongoing.dev
@@ -215,13 +215,13 @@ The following actions will be performed:
   - install qux     4
 
 <><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
++ test "-f" "newfile.txt" (CWD=${BASEDIR}/OPAM/working-dir/.opam-switch/build/ongoing.dev)
++ cat "newfile.txt" (CWD=${BASEDIR}/OPAM/working-dir/.opam-switch/build/ongoing.dev)
++ test "-f" "present" (CWD=${BASEDIR}/OPAM/working-dir/.opam-switch/build/qux.4)
 -> retrieved qux.4  (file://${BASEDIR}/qux)
-test "-f" "newfile.txt" (CWD=${BASEDIR}/OPAM/working-dir/.opam-switch/build/ongoing.dev)
-cat "newfile.txt" (CWD=${BASEDIR}/OPAM/working-dir/.opam-switch/build/ongoing.dev)
 - new!
 -> compiled  ongoing.dev
 -> installed ongoing.dev
-test "-f" "present" (CWD=${BASEDIR}/OPAM/working-dir/.opam-switch/build/qux.4)
 -> compiled  qux.4
 -> installed qux.4
 Done.