## Preface I am unable to write to my client user connected over SSH. No issues with users on server. I run as root, and SELinux is disabled for all the tests below(sudo setenforce 0). Yet, I always get the below error:

[vtian@vbox ~]$ write vtian pts/0
write: vtian is not logged in on pts/0

[vtian@vbox ~]$ who | grep [p]ts/0
vtian    pts/0        2025-06-24 17:55 (10.0.2.2)

If I write to vtian tty1 which is logged in server-side, there is no issues at all. I have another question [here](https://unix.stackexchange.com/questions/797201/unable-to-write-to-self-in-graphical-terminal-session/797235#797235) which is answered, to make sure that it wasn't an issue with my client gnome-terminal. ## Prerequisites I have checked * user is logged in utmp (According to who, loginctl, and last). * user tty is correct (tty returns pts/0). * user can receive messages if writing directly to the fd /dev/pts/0. * user is receiving messages (According to who -T and mesg). * write has s+g permission (setgid) ## Write Version [Edit 1]

vtian@vbox ~]$ sudo rpm -qf $(which write)
util-linux-2.40.2-10.el10.x86_64

## who and last and ls output [Edit 1]

[vtian@vbox ~]$ last | head -n 4
vtian    pts/0        10.0.2.2         Mon Jun 23 16:18   still logged in
vtian    tty1                          Mon Jun 23 16:18   still logged in
reboot   system boot  6.12.0-55.16.1.e Mon Jun 23 16:17   still running
vtian    pts/0        10.0.2.2         Sat Jun 21 16:19 - 16:29  (00:09)
[vtian@vbox ~]$ last | head -n 5
vtian    pts/0        10.0.2.2         Mon Jun 23 16:18   still logged in
vtian    tty1                          Mon Jun 23 16:18   still logged in
reboot   system boot  6.12.0-55.16.1.e Mon Jun 23 16:17   still running
vtian    pts/0        10.0.2.2         Sat Jun 21 16:19 - 16:29  (00:09)
vtian    tty1                          Sat Jun 21 16:18 - 16:29  (00:11)
[vtian@vbox ~]$ who -aT
           system boot  2025-06-23 16:17
vtian    + tty1         2025-06-23 16:18 00:01        4299
           run-level 3  2025-06-23 16:17
vtian    + pts/0        2025-06-23 16:18   .          4903 (10.0.2.2)
           pts/1        2025-06-23 16:18              4939 id=ts/1  term=0 exit=0
[vtian@vbox ~]$ sudo ls -l $(which write)
-rwxr-sr-x. 1 root tty 24152 Feb 13 08:00 /usr/bin/write

## Disk Mount Status [Edit 1] My disk is using LVM. None of the LVs are mounted with nosuid. The only mounts with nosuid are /proc, as well as some stuff in /dev, /sys, and /run. ## loginctl output [Edit 2] I have just found out something really strange and reproducible. Output for loginctl and sudo loginctl on vtian tty1, and loginctl on vtian pts/0 given the condition stated below.

[vtian@vbox ~]$ loginctl
SESSION  UID USER  SEAT  LEADER CLASS   TTY   IDLE SINCE
      2 1000 vtian -     3697   manager -     no   -    
      3 1000 vtian seat0 3149   user    tty1  no   -    
      6 1000 vtian -     3960   user    pts/0 no   -    
3 sessions listed.

Output for sudo loginctl on pts/0

[vtian@vbox ~]$ sudo loginctl
[sudo] password for vtian: 
SESSION  UID USER  SEAT  LEADER CLASS   TTY  IDLE SINCE
      2 1000 vtian -     3697   manager -    no   -    
      3 1000 vtian seat0 3149   user    tty1 no   -    
      6 1000 vtian -     3960   user    -    no   -    

3 sessions listed.

After I run sudo loginctl from vtian pts/0, vtian pts/0 is gone from logind for the rest of the session! If I run loginctl or sudo loginctl from vtian tty, I continue to get the above output! The only way to fix it is by restarting the ssh session. ## Other Outputs [Edit 2]

vtian@vbox ~]$ sudo grep -e @include -e pam_systemd /etc/pam.d/{sshd,common*}
grep: /etc/pam.d/common*: No such file or directory

## PAM Systemd Output [Edit 3]

[root@vbox vtian]# grep -r pam_systemd /etc/pam*
/etc/pam.d/runuser-l:-session	optional	pam_systemd.so

## uname and distro info [Edit 4]

[root@vbox vtian]# uname -a
Linux vbox 6.12.0-55.16.1.el10_0.x86_64 #1 SMP PREEMPT_DYNAMIC Tue Jun 10 18:27:04 UTC 2025 x86_64 GNU/Linux
[root@vbox vtian]# cat /etc/os-release
NAME="Rocky Linux"
VERSION="10.0 (Red Quartz)"
ID="rocky"
ID_LIKE="rhel centos fedora"
VERSION_ID="10.0"
PLATFORM_ID="platform:el10"
PRETTY_NAME="Rocky Linux 10.0 (Red Quartz)"
ANSI_COLOR="0;32"
LOGO="fedora-logo-icon"
CPE_NAME="cpe:/o:rocky:rocky:10::baseos"
HOME_URL="https://rockylinux.org/ "
VENDOR_NAME="RESF"
VENDOR_URL="https://resf.org/ "
BUG_REPORT_URL="https://bugs.rockylinux.org/ "
SUPPORT_END="2035-05-31"
ROCKY_SUPPORT_PRODUCT="Rocky-Linux-10"
ROCKY_SUPPORT_PRODUCT_VERSION="10.0"
REDHAT_SUPPORT_PRODUCT="Rocky Linux"
REDHAT_SUPPORT_PRODUCT_VERSION="10.0"

## strace [Edit 5] I don't know how to interpret the strace data, but it looks to me like write does successfully iterate the vtian pts/0 session, but it seems to disregard it as not belonging to vtian pts/0

[root@vbox vtian]# strace -o /tmp/tracefile write vtian pts/0
write: vtian is not logged in on pts/0
[root@vbox vtian]# grep '/run/systemd/sessions/' /tmp/tracefile
openat(AT_FDCWD, "/run/systemd/sessions/", O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_DIRECTORY) = 3
openat(AT_FDCWD, "/run/systemd/sessions/1", O_RDONLY|O_CLOEXEC) = 3
openat(AT_FDCWD, "/run/systemd/sessions/1", O_RDONLY|O_CLOEXEC) = 3
openat(AT_FDCWD, "/run/systemd/sessions/2", O_RDONLY|O_CLOEXEC) = 3
openat(AT_FDCWD, "/run/systemd/sessions/2", O_RDONLY|O_CLOEXEC) = 3
openat(AT_FDCWD, "/run/systemd/sessions/6", O_RDONLY|O_CLOEXEC) = 3
openat(AT_FDCWD, "/run/systemd/sessions/6", O_RDONLY|O_CLOEXEC) = 3
openat(AT_FDCWD, "/run/systemd/sessions/7", O_RDONLY|O_CLOEXEC) = 3
openat(AT_FDCWD, "/run/systemd/sessions/7", O_RDONLY|O_CLOEXEC) = 3
[root@vbox vtian]# loginctl list-sessions
SESSION  UID USER  SEAT  LEADER CLASS         TTY   IDLE SINCE
      1    0 root  seat0 1249   user-early    tty1  no   -    
      2    0 root  -     1799   manager-early -     no   -    
      6 1000 vtian -     2033   user          pts/0 no   -    
      7 1000 vtian -     2041   manager       -     no   -

I know that this is a failed strace, as if it were successful, there would be an instruction like this after openat(AT_..., ../sessions/7" ...), as this is what it looks like when writing successfully to root tty1

openat(AT_FDCWD, "/run/systemd/sessions/1", O_RDONLY|O_CLOEXEC) = 3
...
newfstatat(AT_FDCWD, "/dev/tty1", {st_mode=S_IFCHR|0620, st_rdev=makedev(0x4, 0x1), ...}, 0) = 0
...
openat(AT_FDCWD, "/dev/tty1", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 3
...

In addition, I don't really know why /dev/pts/0 is invoked here when i'm writing to /dev/tty1

execve("/usr/bin/write", ["write", "root", "/dev/tty1"], 0x7ffc4f216350 /* 30 vars */) = 0
...
ioctl(0, TCGETS, {c_iflag=ICRNL|IXON|IUTF8, c_oflag=NL0|CR0|TAB0|BS0|VT0|FF0|OPOST|ONLCR, c_cflag=B38400|CS8|CREAD, c_lflag=ISIG|ICANON|ECHO|ECHOE|ECHOK|IEXTEN|ECHOCTL|ECHOKE, ...}) = 0
ioctl(0, TCGETS, {c_iflag=ICRNL|IXON|IUTF8, c_oflag=NL0|CR0|TAB0|BS0|VT0|FF0|OPOST|ONLCR, c_cflag=B38400|CS8|CREAD, c_lflag=ISIG|ICANON|ECHO|ECHOE|ECHOK|IEXTEN|ECHOCTL|ECHOKE, ...}) = 0
ioctl(0, TCGETS, {c_iflag=ICRNL|IXON|IUTF8, c_oflag=NL0|CR0|TAB0|BS0|VT0|FF0|OPOST|ONLCR, c_cflag=B38400|CS8|CREAD, c_lflag=ISIG|ICANON|ECHO|ECHOE|ECHOK|IEXTEN|ECHOCTL|ECHOKE, ...}) = 0
fstat(0, {st_mode=S_IFCHR|0620, st_rdev=makedev(0x88, 0), ...}) = 0
readlink("/proc/self/fd/0", "/dev/pts/0", 4095) = 10
newfstatat(AT_FDCWD, "/dev/pts/0", {st_mode=S_IFCHR|0620, st_rdev=makedev(0x88, 0), ...}, 0) = 0
newfstatat(AT_FDCWD, "/dev/pts/0", {st_mode=S_IFCHR|0620, st_rdev=makedev(0x88, 0), ...}, 0) = 0
getuid()                                = 0
getuid()                                = 0
...

```

Essentially, I noticed I am unable to write to my user who is using gnome-terminal. tty returns /dev/pts/1, but I am unable to write there as root. Instead, it returns as follows:

myuser@pegasus:/$ tty
/dev/pts/1
root@pegasus:/# write myuser pts/1
write: myuser is not logged in on pts/1

I have also tried write myuser tty2, and tried not specifying the terminal, but nothing happens. How can I write to my session? The inverse works fine:

myuser@pegasus:/$ write root pts/0
hi!
please respond
root@pegasus:/# 
Message from myuser@pegasus on pts/1 at 22:05 ...
hi!
please respond
EOF

Here is what the logins look like.

root@pegasus:/# who -aT
           system boot  2025-06-19 21:34
           run-level 5  2025-06-19 21:34
myuser ? seat0        2025-06-19 21:34   ?          2982 (login screen)
myuser + tty2         2025-06-19 21:34 00:37        2982 (tty2)
           pts/1        2025-06-19 21:41             25698 id=ts/1  term=0 exit=0

myuser@pegasus:/$ loginctl
SESSION  UID USER      SEAT  LEADER CLASS         TTY   IDLE SINCE
     11    0 root      -     79869  manager-early -     no   -    
      2 1000 myuser seat0 2891   user          tty2  no   -    
      3 1000 myuser -     2911   manager       -     no   -    
    c11    0 root      -     79732  user-early    pts/0 no   -    

4 sessions listed.

OS: xUbuntu 22.04 I want to use the write / wall commands for sending msgs to other users sharing the same computer. But when I try to use the write command, I get the following error:

√ ~ $ who
user1   tty7         2024-05-12 06:40 (:0)
user2  tty8         2024-05-13 06:56 (:1)
user3    tty9         2024-05-16 06:09 (:2)
user4    tty10        2024-05-16 11:54 (:3)
√ ~ $ write user2 tty8
write: effective gid does not match group of /dev/pts/13

The error is the same no matter what variation of the command I try: write user2, write user2 /dev/pts/13 or write user2 pts/13 I have been searching online and found just a few blurbs about the error. One such blurb seemed to suggest this behaviour was intentional, at least for Debian/buntu. https://bugs.launchpad.net/ubuntu/+source/util-linux/+bug/2064685 I did try the advice in the link above to: >If you wish to restore the previous behavior, it should be sufficient to change /usr/bin/write.ul to root:tty 02755. So that now my /etc/bin/write.ul has the setgid bit set: √ ~ $ sudo chmod 02755 /usr/bin/write.ul

√ ~ $ ls /usr/bin/write.ul
-rwxr-sr-x 1 root root 23K Apr  9 10:32 /usr/bin/write.ul*

but doing so has made no change in the error received. Any ideas what more I likely need to do to get these commands working as intended?

I use LinuxMint21, and I go in TTY only when I have an issue with my X session. Today, I went to a TTY, and I saw messages about sysrqd, partially disabled (was not expected), and I have some upgrade to do with fwupdmgr. **I don't talk about the sourced files, like /etc/issue and such, but messages broadcasted like wall only in TTY (like sysrqd when I hit them keyboard shortcuts).** Is there a way or a hack to have those important broadcast messages in my _terminal emulator_? I use xfce4-terminal 0.8.10 TIA.

I'm trying to setup a simple script to run on a cron job that runs in the background and notifies any open terminals of the outcome using the wall command. However when testing, I don't get any output at all. I'm using WSL Ubuntu and zsh via the Terminal app from Microsoft. Running tty and w returns the below, while who returns nothing at all. hardya@GBH-HARDYA1  ~  tty /dev/pts/4 hardya@GBH-HARDYA1  ~  w 09:16:01 up 3 days, 4:30, 0 users, load average: 0.00, 0.00, 0.00 USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT Any ideas?

I'm using crontab to send messages to all users. I wrote */1 * * * * wall $(bash some_shell_script.sh) But the problem is I always have to press Ctrl+D to end the message. How can I solve this??

I have tried wall, but it does not show the message to local terminal. Can I show it to local terminal, too? The remote SSH and the local GUI terminal are the same user account. The reason why I am trying to do is that I want to use it basically for "copy and paste" between host and guest (VM), when the hypervisor's "copy and paste" feature is not working. I could save the text to a text file and then reload it on the guest, but just displaying the text like wall would be easier.

The description for the wall command states that it sends a message to *all* logged in users. However, the man page describes a flag, -g --group, which allows the sender to limit messages to a specified group: > -g, --group group Limit printing message to members of group defined as a group argument. The argument can be group name or GID. However, I am only able to send messages to all logged in users. I have tried this command with: - -g my_group, - --group my_group, - -g "my_group", - --group "my_group", - --group=my_group In addition, I have tried all of the above by replacing "my_group" (the group name) with the group ID to no avail. I have also tried placing the flags *after* the message. None of this works to limit the messages to a given group. All messages go to all users. Am I misunderstanding the flag? The syntax? Is this command broken? Or is the man page simply incorrect? Please do not offer alternative commands, I am aware of their existence. I want to know how to use a listed option or why the option is not working correctly. I am using Ubuntu 20.04

I am using Ubuntu 16.04 and have enabled automatic updates and reboots. Version of unattended-upgrades is 0.90ubuntu0.9. When there is pending reboot and I am logged in to the server I keep getting these notifications to my session: Broadcast message from root@server (Fri 2018-04-06 10:30:00 EEST): The system is going down for reboot at Sat 2018-04-07 03:30:00 EEST! Broadcast message from root@server (Fri 2018-04-06 11:30:00 EEST): The system is going down for reboot at Sat 2018-04-07 03:30:00 EEST! Broadcast message from root@server (Fri 2018-04-06 12:30:00 EEST): The system is going down for reboot at Sat 2018-04-07 03:30:00 EEST! Broadcast message from root@server (Fri 2018-04-06 13:30:00 EEST): The system is going down for reboot at Sat 2018-04-07 03:30:00 EEST! Broadcast message from root@server (Fri 2018-04-06 14:30:00 EEST): The system is going down for reboot at Sat 2018-04-07 03:30:00 EEST! Can I prevent these messages from being sent to shell as it is annoying to receice them and the users know that the server may reboot during maintenance window? I checked /etc/apt/apt.conf.d/50unattended-upgrades but I found only email notification settings there.

I know this is a very unusual question but i had to create a bash script for a school project and I created a systemd service which calls a script on startup. Script contained (i think, cant check cause perma wall command) :

#!/bin/bash
until/while (ls /dev/pts/ | wc -l != 0) ## not sure if i added the != 0
do
   wall -n "this is a broadcast"
done

Is there a way to disable this script/wall command? os is centOS stream 9 minimal installation (no gui) running in VirtualBox on MacOS

I'm not sure what is going on or which command causes the unexpected behavior, so I'll post everything I've done: I have created a script onreceive.sh containing:

#!/bin/bash
read INCOMING
wall --nobanner "${INCOMING}.wav"
wall --nobanner "${INCOMING}"

Then I ran:

socat -u tcp-listen:7777,fork system:./onreceive.sh

Then I made a connection (I used PuTTY, but netcat probably works as well) to port 7777 and sent one line of text ("asdf"). The output I got is:

.wav


asdf

What I expected:

asdf.wav


asdf

A tool that runs day and night sometimes posts crucial information to the wall. Is there any way to redirect this output to a file for when I'm asleep? Alternatively, does wall keep a log of messages posted to it or is there a way to enable it?

I received some messages here: [root@localhost kvm]# Broadcast message from root@localhost.localdomain (pts/1) (Thu Jun 6 08:04:26 2019): hello Broadcast message from root@localhost.localdomain (pts/1) (Thu Jun 6 08:05:02 2019): hello How has this messagen been sent to me? And how can I reply to it?

Using Linux Slackware 14.2, KDE. I created a script in Linux with Russian text that I want to output through wall: #!/bin/bash wall <<< 'Сообщение' Instead of text I see the characters codes: \320\241\320\276\320\276\320\261\321\211\320\265\320\275\320\270\320\265 I added to ~/.bashrc: locale=C_UTF8 Then did: $ source ~/.bashrc But it didn't work. How to fix this?

I can't find an answer for this and it may be because I don't know how to phrase the question. I'm using wall to broadcast a message to open terminals once a day. When it does, the terminal users' prompts will disappear until they press ENTER. The wall command is wall -n wall message And for lack of a better explanation, here is what it looks like on the users' terminal: As you can see it just hangs. Pressing ENTER or doing anything will get me back to a prompt. In fact, even though it doesn't look like a prompt, it is, because instead of pressing ENTER I can do a command, or press up arrow to see previous commands, etc. It's not critical, it just bugs me. I have considered that maybe it's by design, to force users to acknowledge that they've seen the message, although the fact that it only _looks_ like it's not a prompt seems like it defeats that purpose.

Why does echo foo | wall work but cat | wall not work? In the latter case, I enter a couple lines into cat, and in theory they should pipe to wall; however, nothing happens.

When I use echo "hi" | wall on a device I have running Ubuntu 14.04 I get back: Broadcast Message from rescue@ws1-/share/locale-langpack/en_CA.UTF-8.utf8/LC_ID (/dev/pts/2) at 14:19 ... hi But when I run the same command on my desktop running Ubuntu 16.04 I get back nothing. Permissions for Wall: -rwxr-sr-x 1 root tty 27368 Jun 14 17:51 /usr/bin/wall Results of tty: /dev/pts/5 Results of w: 12:56:21 up 2:40, 1 user, load average: 0.66, 0.65, 0.79 USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT philip tty7 :0 10:17 2:39m 1:47 2.35s i3 Why wouldn't this be working, how can I debug the issue? ---------- Also tried echo hi > /tmp/msg && sudo wall /tmp/msg *Normally using i3 but I also tried logging out and back in with unity and got the same results.*