diff --git a/README.md b/README.md
index 53f9d69..baec92d 100644
--- a/README.md
+++ b/README.md
@@ -51,14 +51,12 @@ $ pounce -s ''
 
 # TODO
 
-- [ ] apply tests.
 - [ ] deal with colons in file names.
-- [ ] deal with no EOL last line.
-- [ ] apply: only generate backup files if content actually changed.
-- [ ] apply: read/write piece wise.
+- [ ] deal with no EOL on last line of files.
 - [ ] `\n` vs `\r\n`?
-- [ ] example in README could be better.
-- [ ] cli flags can be better phrased.
+- [ ] apply: only generate backup files if content actually changed?
+- [ ] apply: read/write piece wise.
+- [ ] cli flags docs can be better phrased.
 
 # Disclaimer
 
diff --git a/common.go b/common.go
index b8efa3f..bcf2bb9 100644
--- a/common.go
+++ b/common.go
@@ -19,9 +19,16 @@ func trimPath(p string) string {
 
 var commonConfig struct {
 	print, nowd, collect, apply bool
+	dir                         string
 }
 
 var commonFlags = []cli.Flag{
+	&cli.StringFlag{
+		Name:        "dir",
+		Aliases:     []string{"d"},
+		Destination: &commonConfig.dir,
+		Usage:       "set working directory",
+	},
 	&cli.BoolFlag{
 		Name:        "print",
 		Aliases:     []string{"p"},
diff --git a/pounce.go b/pounce.go
index 78d21b9..d895170 100644
--- a/pounce.go
+++ b/pounce.go
@@ -17,6 +17,12 @@ var app = cli.App{
 	Version:                version,
 	Flags:                  append(append(commonFlags, collectFlags...), applyFlags...),
 	Action: func(c *cli.Context) error {
+		if dir := commonConfig.dir; dir != "" {
+			if err := os.Chdir(dir); err != nil {
+				return fmt.Errorf("chdir: %w", err)
+			}
+		}
+
 		args := c.Args().Slice()
 
 		if commonConfig.collect && commonConfig.apply ||
@@ -68,7 +74,7 @@ func both(werr io.Writer, args []string) error {
 	cmd.Stderr = os.Stderr
 
 	if err := cmd.Run(); err != nil {
-		if err := err.(*exec.ExitError); err != nil {
+		if err, ok := err.(*exec.ExitError); ok && err != nil {
 			return fmt.Errorf("editor exited with code %d", err.ExitCode())
 		}
 
diff --git a/tests/apply.clitest b/tests/apply.clitest
deleted file mode 100644
index 6a22c72..0000000
--- a/tests/apply.clitest
+++ /dev/null
@@ -1 +0,0 @@
-$ cd "${TESTROOT}/fixtures"
diff --git a/tests/both.clitest b/tests/both.clitest
new file mode 100644
index 0000000..16853aa
--- /dev/null
+++ b/tests/both.clitest
@@ -0,0 +1,85 @@
+$ dir0=$(mktemp -d)
+$ trap "rm -fR ${dir0}" 0
+$ cd "${dir0}"
+$ cp -r "${TESTROOT}/fixtures" .
+$ ${POUNCE} -d fixtures -c --nowd -rs '' > before
+$ cat before | sed -e 's/dogs/cats/g' > after
+$ ${POUNCE} -d fixtures -a < after
+$ find fixtures -type f -not -name binary -exec cat {} \;
+I like cats.
+Cats are the best.
+meow
+pigs are the best!
+fish are the best!
+cats are the best!
+cats are the best!
+meow
+$
+$ # with backup files
+$ dir1=$(mktemp -d)
+$ trap "rm -fR ${dir1}" 0
+$ cd "${dir1}"
+$ cp -r "${TESTROOT}/fixtures" .
+$ ${POUNCE} -d fixtures -a --bak _bak < "${dir0}/after"
+$ find . -type f -print
+./fixtures/README.md_bak
+./fixtures/README.md
+./fixtures/some/dir/animals.txt
+./fixtures/some/dir/animals.txt_bak
+./fixtures/some/binary
+$ cat ./fixtures/README.md_bak
+I like dogs.
+Cats are the best.
+meow
+$ cat ./fixtures/README.md
+I like cats.
+Cats are the best.
+meow
+$
+$ # with editor
+$ dir2=$(mktemp -d)
+$ trap "rm -fR ${dir2}" 0
+$ cd "${dir2}"
+$ cp -r "${TESTROOT}/fixtures" .
+$ EDITOR=cat ${POUNCE} --nowd -rs 'meow'
+fixtures/README.md:3:meow
+fixtures/some/dir/animals.txt:5:meow
+$ echo "#!/bin/sh" > ./mod.sh
+$ echo "exec sed -i '' -e 's/dog/cat/g' \$1" >> ./mod.sh
+$ chmod +x ./mod.sh
+$ EDITOR=./mod.sh ${POUNCE} --nowd -rs 'dog'
+$ find . -type f -not -name binary -and -not -name mod.sh -exec cat {} \;
+I like cats.
+Cats are the best.
+meow
+pigs are the best!
+fish are the best!
+cats are the best!
+cats are the best!
+meow
+$
+$ # wd
+$ dir3=$(mktemp -d)
+$ trap "rm -fR ${dir3}" 0
+$ cd "${dir3}"
+$ cp -r "${TESTROOT}/fixtures" .
+$ ${POUNCE} -d fixtures -c -rs '' > before
+$ cat before | sed -e 's/dogs/cats/g' > after
+$ ${POUNCE} -a < after #=> --exit 1
+$ ${POUNCE} -d fixtures -a < after
+$
+$ # abs
+$ dir4=$(mktemp -d)
+$ trap "rm -fR ${dir4}" 0
+$ cd "${dir4}"
+$ cp -r "${TESTROOT}/fixtures" .
+$ ${POUNCE} --abs -d fixtures -c -rs '' | sed -e 's/dog/cat/g' | ${POUNCE} -d fixtures -a
+$ find fixtures -type f -not -name binary -and -not -name mod.sh -exec cat {} \;
+I like cats.
+Cats are the best.
+meow
+pigs are the best!
+fish are the best!
+cats are the best!
+cats are the best!
+meow