I have a laptop running Windows 10 (or Windows 11). I can ssh into my Ubuntu computer with ssh [email protected], but I'd like to either (a) use a GUI app from Windows or (b) use the entire desktop from Windows. Ideally, I'd like to do this via X forwarding, rather than VNC or RDP. Note that I'm not using Wayland here.
How can I do this?
This hides output from the first command, and prints Oops to stderr if it fails. So far, so good.
#!/usr/bin/env bash
invalid_command > /dev/null 2>&1 || >&2 echo "Oops"
echo hi
That outputs this:
Oops
hi
But I need to exit as well as printing a message if the first command failed. So I tried using parenthesis.
#!/usr/bin/env bash
invalid_command > /dev/null 2>&1 || ( >&2 echo "Oops" ; exit )
echo hi
Here's the output of that:
Oops
hi
But now the exit doesn't work because it's doing it in a subshell, causing it to print hi, even though I wanted the script to exit.
So, how do I get Bash to echo some text and exit if a specific command failed using the || operator? I'm aware that I can use an if one-liner to do that, but I'd prefer to not have to use a full if statement if I can avoid it.
#!/usr/bin/env bash
if [ "$(invalid_command > /dev/null 2>&1 ; printf $?)" != "0" ]; then >&2 echo 'Oops' ; exit 1; fi
I like the Micro text editor. I prefer it to nano, personally. However, even when I have it installed, Git defaults to nano. How can I change what text editor git commit uses?
I'm using Ubuntu 21.10. If I mess up, I can re-run the last command with !!. Here's an example:
$ apt update
Reading package lists... Done
E: Could not open lock file /var/lib/apt/lists/lock - open (13: Permission denied)
E: Unable to lock directory /var/lib/apt/lists/
W: Problem unlinking the file /var/cache/apt/pkgcache.bin - RemoveCaches (13: Permission denied)
W: Problem unlinking the file /var/cache/apt/srcpkgcache.bin - RemoveCaches (13: Permission denied)
$ sudo !!
sudo apt update
[sudo] password for [me]:
...
Fetched 336 kB in 2s (206 kB/s)
Reading package lists... Done
Building dependency tree
Reading state information... Done
98 packages can be upgraded. Run 'apt list --upgradable' to see them.
That's fine, but instead of rerunning the previous command, how can I run the one before it? Like this:
$ echo hi
hi
$ echo hello
hello
$ !! <-- I'm trying to get that to run 'echo hi'
hello
Basically, here's what I'm looking for
$ echo hi
hi
$ echo hello
hello
$ ??? <-- What can I put here to get it to run 'echo hi'?
echo hello!
hello!
So, given that !! runs the last command, how can I run the command before the previous one? In my example, instead of typing !!, what can I run to execute echo hi?
So I ran a stupid command as root (DO NOT RUN THIS)
# chown -R root:root /{usr,lib,var,etc,bin,sbin,tools}
So... oops. I happened to have a root shell open (from when I caused this), so I was able to get sudo working by doing
# chown root:root /usr/bin/sudo
# chmod 4755 /usr/bin/sudo
Yay, sudo works again. I wanted to install a package (ncdu), so I ran sudo apt-get install ncdu.
$ sudo apt-get install ncdu
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following NEW packages will be installed:
ncdu
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 0 B/43.4 kB of archives.
After this operation, 106 kB of additional disk space will be used.
Selecting previously unselected package ncdu.
(Reading database ... 233654 files and directories currently installed.)
Preparing to unpack .../ncdu_1.15.1-1_amd64.deb ...
Unpacking ncdu (1.15.1-1) ...
Setting up ncdu (1.15.1-1) ...
Processing triggers for man-db (2.9.4-2) ...
/usr/bin/mandb: can't chmod /var/cache/man/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/es/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/es/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/es/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/zh_TW/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/zh_TW/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/zh_TW/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/fi/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/fi/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/fi/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/de/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/de/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/de/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/uk/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/uk/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/uk/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/sr/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/sr/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/sr/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/sl/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/sl/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/sl/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/nb/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/nb/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/nb/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/pt/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/pt/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/pt/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/ru/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/ru/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/ru/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/ko/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/ko/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/ko/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/it/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/it/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/it/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/fr/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/fr/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/fr/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/et/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/et/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/et/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/ca/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/ca/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/ca/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/tr/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/tr/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/tr/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/nl/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/nl/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/nl/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/fr.UTF-8/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/fr.UTF-8/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/fr.UTF-8/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/hu/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/hu/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/hu/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/fr.ISO8859-1/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/fr.ISO8859-1/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/fr.ISO8859-1/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/sv/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/sv/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/sv/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/id/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/id/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/id/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/el/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/el/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/el/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/pt_BR/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/pt_BR/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/pt_BR/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/ro/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/ro/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/ro/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/zh_CN/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/zh_CN/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/zh_CN/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/cs/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/cs/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/cs/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/gl/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/gl/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/gl/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/da/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/da/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/da/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/pl/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/pl/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/pl/1053532: Permission denied
/usr/bin/mandb: can't chmod /var/cache/man/ja/CACHEDIR.TAG: Operation not permitted
/usr/bin/mandb: can't remove /var/cache/man/ja/CACHEDIR.TAG: Permission denied
/usr/bin/mandb: fopen /var/cache/man/ja/1053532: Permission denied
Clearly I didn't do enough to fix my system. I'd prefer not to reinstall the OS if possible, but I have a root shell (it's a physical laptop in front of me), so I'm wondering how to fix apt so I can install packages again. I'm using Kubuntu 21.10.
I need to stop the GUI and access a TTY for the NVIDIA drivers. I found this question. However, when I tried sudo service lightdm stop (or the same with gdm), it said this:
$ sudo service lightdm stop
Failed to stop lightdm.service: Unit lightdm.service not loaded.
$ sudo service gdm stop
Failed to stop gdm.service: Unit gdm.service not loaded.
I'd prefer not have to mess with Grub, as I only need to stop the GUI once. So, how do I stop the GUI to use a TTY with no GUI running at all in Kubuntu 21.10?
Note: I know how to access a TTY. But once I'm in the TTY, I need to stop the GUI, as the NVIDIA driver installer wants me to be in a TTY and have the GUI not running.
So I have a script like this:
somecommad | grep --invert-match something
I'd like to be able to conditionally run a different command if somecommand fails. Here's what I tried:
somecommand | grep --invert-match something || {
echo 'Oops'
}
But that didn't work (the grep wasn't executed). What is the proper way to do this?