Re: [PATCH iproute2-next] "ip help" wrong output, exit code.

[Dmitri Seletski <drjoms@gmail.com>]

I am confused.

Whats the next step here?

Regards

Dmitri

On 6/22/26 18:47, Dmitri Seletski wrote:
> Hello David,
>
>
> Based on change introduced:
>
> Two samples of "ip help" with demonstration of exit code and standard 
> output are below.
>
> This is in line with what expect.
>
>
> dimkosPC~/compiled/iproute2-next #if ./ip/ip help a >>/dev/null  ; 
> then echo help triggered  ; else echo error code triggered  ;fi  #this 
> redirects standard output  to /dev/null, so text missing is not error,
> but standard text
> help triggered
>
> dimkosPC~/compiled/iproute2-next #if ./ip/ip help   ; then echo help 
> triggered  ; else echo error code triggered  ;fi
> Usage: ip [ OPTIONS ] OBJECT { COMMAND | help }
>       ip [ -force ] -batch filename
> where  OBJECT := { address | addrlabel | fou | help | ila | ioam | 
> l2tp | link |
>                   macsec | maddress | monitor | mptcp | mroute | mrule |
>                   neighbor | neighbour | netconf | netns | nexthop | 
> ntable |
>                   ntbl | route | rule | sr | stats | tap | tcpmetrics |
>                   token | tunnel | tuntap | vrf | xfrm }
>       OPTIONS := { -V[ersion] | -s[tatistics] | -d[etails] | -r[esolve] |
>                    -h[uman-readable] | -iec | -j[son] | -p[retty] |
>                    -f[amily] { inet | inet6 | mpls | bridge | link } |
>                    -4 | -6 | -M | -B | -0 |
>                    -l[oops] { maximum-addr-flush-attempts } | -echo | 
> -br[ief] |
>                    -o[neline] | -t[imestamp] | -ts[hort] | -b[atch] 
> [filename] |
>                    -rc[vbuf] [size] | -n[etns] name | -N[umeric] | 
> -a[ll] |
>                    -c[olor]}
> help triggered
>
> Two samples of command that is broken on purpose.
>
> dimkosPC~/compiled/iproute2-next #if ./ip/ip idontexist   ; then echo 
> help triggered  ; else echo error code triggered  ;fi
> Object "idontexist" is unknown, try "ip help".
> error code triggered
>
> dimkosPC~/compiled/iproute2-next #if ./ip/ip idontexist  >>/dev/null 
>  ; then echo help triggered  ; else echo error code triggered  ;fi 
>  #this redirects standard output  to /dev/null, so text missing is not 
> error, but standard text
> Object "idontexist" is unknown, try "ip help".
> error code triggered
>
> This works as expected as per my understanding.
>
>
> Not everything is fixed, but chunk of things fixed is better than non 
> of it.
>
> for example:
>
> if ip  add help    ; then echo help triggered  ; else echo error code 
> triggered  ;fi  #this redirects standard output  to /dev/null, so text 
> missing is not error, but standard text
> Usage: ip address {add|change|replace} IFADDR dev IFNAME [ LIFETIME ]
>                                                      [ CONFFLAG-LIST ]
>       ip address del IFADDR dev IFNAME [mngtmpaddr]
>       ip address {save|flush} [ dev IFNAME ] [ scope SCOPE-ID ] [ to 
> PREFIX ]
>                            [ FLAG-LIST ] [ label LABEL ] [ { up | down 
> } ]
>       ip address [ show [ dev IFNAME ] [ scope SCOPE-ID ] [ master 
> DEVICE ]
>                         [ nomaster ]
>                         [ type TYPE ] [ to PREFIX ] [ FLAG-LIST ]
>                         [ label LABEL ] [ { up | down } ] [ vrf NAME ]
>                         [ proto ADDRPROTO ] ]
>       ip address {showdump|restore}
> IFADDR := PREFIX | ADDR peer PREFIX
>          [ broadcast ADDR ] [ anycast ADDR ]
>          [ label IFNAME ] [ scope SCOPE-ID ] [ metric METRIC ]
>          [ proto ADDRPROTO ]
> SCOPE-ID := [ host | link | global | NUMBER ]
> FLAG-LIST := [ FLAG-LIST ] FLAG
> FLAG  := [ permanent | dynamic | secondary | primary |
>           [-]tentative | [-]deprecated | [-]dadfailed | temporary |
>           CONFFLAG-LIST ]
> CONFFLAG-LIST := [ CONFFLAG-LIST ] CONFFLAG
> CONFFLAG  := [ home | nodad | mngtmpaddr | noprefixroute | autojoin ]
> LIFETIME := [ valid_lft LFT ] [ preferred_lft LFT ]
> LFT := forever | SECONDS
> ADDRPROTO := [ NAME | NUMBER ]
> TYPE := { amt | bareudp | bond | bond_slave | bridge | bridge_slave |
>          dsa | dummy | erspan | geneve | gre | gretap | gtp | hsr |
>          ifb | ip6erspan | ip6gre | ip6gretap | ip6tnl |
>          ipip | ipoib | ipvlan | ipvtap |
>          macsec | macvlan | macvtap | netdevsim |
>          netkit | nlmon | pfcp | rmnet | sit | team | team_slave |
>          vcan | veth | vlan | vrf | vti | vxcan | vxlan | wwan |
>          xfrm | virt_wifi }
> error code triggered
>
> This is still problematic.
>
>
> But so far code leaves "ip help" command/argument in better shape than 
> it found it in.
>
>
> I may try improve things more, but lets submit what we already have 
> "better", please.
>
> Kind Regards
>
> Dmitri Seletski
>
>
> On 6/22/26 17:44, David Laight wrote:
>> On Mon, 22 Jun 2026 07:57:00 -0700
>> Stephen Hemminger <stephen@networkplumber.org> wrote:
>>
>>> On Sun, 21 Jun 2026 22:48:59 +0100
>>> Dmitri Seletski <drjoms@gmail.com> wrote:
>>>
>>>>  From 0805e07105cd15c5b94271a4706e50e3c65dbde5 Mon Sep 17 00:00:00 
>>>> 2001
>>>> From: Dmitri Seletski <drjoms@gmail.com>
>>>> Date: Sun, 21 Jun 2026 22:12:43 +0100
>>>> Subject: [PATCH iproute2-next]  "ip help" wrong output, exit code.
>>>>
>>>> Changed output of "ip help" from standard error to standard output. 
>>>> And
>>>> Exit is now 0 instead of -1. "ip help|grep bridge" - now gives bridge
>>>> syntax instead of flooding user with everything from "ip help".
>>>> ---
>>>> ip/ip.c | 4 ++--
>>>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/ip/ip.c b/ip/ip.c
>>>> index e4b71bde..4627b61c 100644
>>>> --- a/ip/ip.c
>>>> +++ b/ip/ip.c
>>>> @@ -56,7 +56,7 @@ static void usage(void) __attribute__((noreturn));
>>>>
>>>> static void usage(void)
>>>> {
>>>> -fprintf(stderr,
>>>> +fprintf(stdout,
>>>> "Usage: ip [ OPTIONS ] OBJECT { COMMAND | help }\n"
>>>> "       ip [ -force ] -batch filename\n"
>>>> "where  OBJECT := { address | addrlabel | fou | help | ila | ioam | 
>>>> l2tp
>>>> | link |\n"
>>>> @@ -72,7 +72,7 @@ static void usage(void)
>>>> "                    -o[neline] | -t[imestamp] | -ts[hort] | -b[atch]
>>>> [filename] |\n"
>>>> "                    -rc[vbuf] [size] | -n[etns] name | -N[umeric] |
>>>> -a[ll] |\n"
>>>> "                    -c[olor]}\n");
>>>> -exit(-1);
>>>> +exit(0);
>>>> }
>>> Your mailer damages white space.
>>>
>> The output also needs to depend on whether these is a 'usage' error or
>> if 'help' is requested.
>> Code code is correct for the former - except it should do exit(1).
>>
>>     David
>>
>>