introduce `—workdir` option for docker exec

Signed-off-by: Nicolas De Loof <nicolas.deloof@gmail.com>

cli/command/container/exec.go

@@ -24,6 +24,7 @@ type execOptions struct {
 	user        string
 	privileged  bool
 	env         opts.ListOpts
+	workdir     string
 	container   string
 	command     []string
 }
@@ -57,6 +58,7 @@ func NewExecCommand(dockerCli command.Cli) *cobra.Command {
 	flags.StringVarP(&options.user, "user", "u", "", "Username or UID (format: <name|uid>[:<group|gid>])")
 	flags.BoolVarP(&options.privileged, "privileged", "", false, "Give extended privileges to the command")
 	flags.VarP(&options.env, "env", "e", "Set environment variables")
+	flags.StringVarP(&options.workdir, "workdir", "w", "", "Working directory inside the container")
 	flags.SetAnnotation("env", "version", []string{"1.25"})
 
 	return cmd
@@ -190,6 +192,7 @@ func parseExec(opts execOptions, configFile *configfile.ConfigFile) *types.ExecC
 		Cmd:        opts.command,
 		Detach:     opts.detach,
 		Env:        opts.env.GetAll(),
+		WorkingDir: opts.workdir,
 	}
 
 	// If -d is not set, attach to everything by default

contrib/completion/bash/docker

@@ -1439,7 +1439,7 @@ _docker_container_exec() {
 
 	case "$cur" in
 		-*)
-			COMPREPLY=( $( compgen -W "--detach -d --detach-keys --env -e --help --interactive -i --privileged -t --tty -u --user" -- "$cur" ) )
+			COMPREPLY=( $( compgen -W "--detach -d --detach-keys --env -e --help --interactive -i --privileged -t --tty -u --user --workdir -w" -- "$cur" ) )
 			;;
 		*)
 			__docker_complete_containers_running

contrib/completion/fish/docker.fish

@@ -174,6 +174,7 @@ complete -c docker -A -f -n '__fish_seen_subcommand_from exec' -s d -l detach -d
 complete -c docker -A -f -n '__fish_seen_subcommand_from exec' -l help -d 'Print usage'
 complete -c docker -A -f -n '__fish_seen_subcommand_from exec' -s i -l interactive -d 'Keep STDIN open even if not attached'
 complete -c docker -A -f -n '__fish_seen_subcommand_from exec' -s t -l tty -d 'Allocate a pseudo-TTY'
+complete -c docker -A -f -n '__fish_seen_subcommand_from exec' -s w -l workdir -d 'Working directory inside the container'
 complete -c docker -A -f -n '__fish_seen_subcommand_from exec' -a '(__fish_print_docker_containers running)' -d "Container"
 
 # export

contrib/completion/zsh/_docker

@@ -745,6 +745,7 @@ __docker_container_subcommand() {
                 "($help)--privileged[Give extended Linux capabilities to the command]" \
                 "($help -t --tty)"{-t,--tty}"[Allocate a pseudo-tty]" \
                 "($help -u --user)"{-u=,--user=}"[Username or UID]:user:_users" \
+                "($help -w --workdir)"{-w=,--workdir=}"[Working directory inside the container]:directory:_directories"
                 "($help -):containers:__docker_complete_running_containers" \
                 "($help -)*::command:->anycommand" && ret=0
             case $state in

docs/reference/commandline/exec.md

@@ -29,6 +29,7 @@ Options:
       --privileged     Give extended privileges to the command
   -t, --tty            Allocate a pseudo-TTY
   -u, --user           Username or UID (format: <name|uid>[:<group|gid>])
+  -w, --workdir        Working directory inside the container  
 ```
 
 ## Description
@@ -86,6 +87,20 @@ This will create a new Bash session in the container `ubuntu_bash` with environm
 variable `$VAR` set to "1". Note that this environment variable will only be valid 
 on the current Bash session.
 
+By default `docker exec` command runs in the same working directory set when container was created.
+
+```bash
+$ docker exec -it ubuntu_bash pwd
+/
+```
+
+You can select working directory for the command to execute into
+
+```bash
+$ docker exec -it -w /root ubuntu_bash pwd
+/root
+```
+
 
 ### Try to run `docker exec` on a paused container