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Editor to share with you what to do if Ubuntu16.04 cannot switch root permissions. I hope you will get something after reading this article. Let's discuss it together.

Find a problem

Found that you could not switch to root permissions during su root. Display: / usr/local/bin/zsh has no files or directories

After thinking about the problem, I suddenly remembered that I wanted to change the shell theme some time ago, so I installed zsh and oh-my-zsh. I didn't feel as good as bash for a while (purely personal feeling), so sudo apt remove zsh.

The default shell was changed to zsh at that time:

Chsh-s / bin/zsh

So what exactly did chsh change? Chsh-s actually modifies the line in your / etc/passwd file that corresponds to your user name, which we can check:

Shanlei@shanlei-Lenovo-ideapad-110-15ISK etc/passwd $cat / etc/passwd | grep ^ ISK-15ISK etc/passwd $

Solution method

Enter passwd:

Sudo vim / etc/passwd

We can see:

Root:x:0:0:root:/root:/usr/local/bin/zshdaemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologinbin:x:2:2:bin:/bin:/usr/sbin/nologinsys:x:3:3:sys:/dev:/usr/sbin/nologinsync:x:4:65534:sync:/bin:/bin/syncgames:x:5:60:games:/usr/games:/usr/sbin/nologinman:x:6:12: Man:/var/cache/man:/usr/sbin/nologinlp:x:7:7:lp:/var/spool/lpd:/usr/sbin/nologinmail:x:8:8:mail:/var/mail:/usr/sbin/nologinnews:x:9:9:news:/var/spool/news:/usr/sbin/nologinuucp:x:10:10:uucp:/var/spool/uucp:/usr/sbin/nologinproxy:x:13:13:proxy:/bin:/usr/sbin/nologinwww- Data:x:33:33:www-data:/var/www:/usr/sbin/nologinbackup:x:34:34:backup:/var/backups:/usr/sbin/nologinlist:x:38:38:Mailing List Manager:/var/list:/usr/sbin/nologinirc:x:39:39:ircd:/var/run/ircd:/usr/sbin/nologingnats:x:41:41:Gnats Bug-Reporting System (admin): / var/lib/gnats:/usr/sbin/nologinnobody:x:65534 : 65534:nobody:/nonexistent:/usr/sbin/nologinsystemd-timesync:x:100:102:systemd Time Synchronization ,: / run/systemd:/bin/falsesystemd-network:x:101:103:systemd Network Management,:/run/systemd/netif:/bin/falsesystemd-resolve:x:102:104:systemd Resolver,:/run/systemd/resolve:/bin/falsesystemd-bus-proxy:x:103:105:systemd Bus Proxy : / run/systemd:/bin/falsesyslog:x:104:108::/home/syslog:/bin/false_apt:x:105:65534::/nonexistent:/bin/falsemessagebus:x:106:110::/var/run/dbus:/bin/falseuuidd:x:107:111::/run/uuidd:/bin/falselightdm:x:108:114:Light Display Manager:/var/lib/lightdm:/bin/falsewhoopsie:x:109:116::/nonexistent:/bin/falseavahi-autoipd:x:110:119:Avahi autoip daemon : / var/lib/avahi-autoipd:/bin/falseavahi:x:111:120:Avahi mDNS daemon,:/var/run/avahi-daemon:/bin/falsednsmasq:x:112:65534:dnsmasq,:/var/lib/misc:/bin/falsecolord:x:113:123:colord colour management daemon,:/var/lib/colord:/bin/falsespeech-dispatcher:x:114:29:Speech Dispatcher,:/var/run/speech-dispatcher:/bin/falsehplip:x:115:7:HPLIP system user : / var/run/hplip:/bin/falsekernoops:x:116:65534:Kernel Oops Tracking Daemon,:/:/bin/falsepulse:x:117:124:PulseAudio daemon,:/var/run/pulse:/bin/falsertkit:x:118:126:RealtimeKit,:/proc:/bin/falsesaned:x:119:127::/var/lib/saned:/bin/falseusbmux:x:120:46:usbmux daemon,:/var/lib/usbmux:/bin/falseshanlei:x:1000:1000:shanlei : / home/shanlei:/bin/zsh

Because what I want is the default bash, I modified the first and last lines of the passwd file:

The / usr/local/bin/bash in the first line is changed to / usr/local/bin/zsh, which is for the root user:

Root:x:0:0:root:/root:/usr/local/bin/bash

Change the / bin/bash on the last line to / bin/zsh, which should consist of the login user name and computer name of each computer:

Shanlei:x:1000:1000:shanlei,:/home/shanlei:/bin/bash

Save exit, restart shell, switch root permissions, and find that / usr/local/bin/bash has no files or directories

Check the bash installation location:

Shanlei@shanlei-Lenovo-ideapad-110-15ISK etc/bash.bashrc $whereis bashbash: / bin/bash / etc/bash.bashrc / usr/share/man/man1/bash.1.gzshanlei@shanlei-Lenovo-ideapad-110-15ISK etc/bash.bashrc $

Find that the execution file of bash is in / bin/bash, so modify the first line of / etc/passwd file again:

Root:x:0:0:root:/root:/bin/bash

Then change the default shell to bash:

Chsh-s / bin/bash

Switch again:

Shanlei@shanlei-Lenovo-ideapad-110-15ISK root@shanlei-Lenovo-ideapad-110 15ISK:~# $su-password:

Success ~

-Beautiful dividing line-

There are two other ways to modify the default shell of ubuntu:

Ln-s: force the soft link of / bin/sh to bash: sudo ln-s / bin/bash / bin/sh

Dpkg-reconfigure dash: this method is recommended in Ubuntu: sudo dpkg-reconfigure dash, a pop-up option, set "dash as the default shell" and select no.

How do I check what shell is installed on my machine?

Shanlei@shanlei-Lenovo-ideapad-110-15ISK etc/shells# / etc/shells $cat / ISK / etc/shells: valid login shells/bin/sh/bin/dash/bin/bash/bin/rbashshanlei@shanlei-Lenovo-ideapad-110-15ISK Vol $

How do I check which shell I am currently using? (note that SHELL must be capitalized!)

Shanlei@shanlei-Lenovo-ideapad-110-15ISKVOR $echo $SHELL/bin/bashshanlei@shanlei-Lenovo-ideapad-110-15ISKRV $

After executing zsh, I check that the current shell type is still / bin/bash?

The current shell is a big environment for a logged-in user, while the bash or zsh we use only starts a bash or zsh interpreter program and does not change the environment. If you want to change the environment, you must use chsh.

After reading this article, I believe you have a certain understanding of "Ubuntu16.04 can not switch root permissions". If you want to know more about it, you are welcome to follow the industry information channel. Thank you for reading!

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