problem found
When su root, I found that I could not switch to root privileges. Display: /usr/local/bin/zsh 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. After using it for a while, I felt that bash was not easy to use (pure personal feeling), so sudo apt remove zsh Up.
At that time, the default shell was changed to zsh:
chsh -s /bin/zsh
So where did chsh change? chsh -s actually changed the line corresponding to your username in your /etc/passwd file. We can check:
shanlei@shanlei-Lenovo-ideapad-110-15ISK:~$ cat /etc/passwd|grep ^shanlei
shanlei:x:1000:1000:shanlei,,,:/home/shanlei:/bin/zsh
shanlei@shanlei-Lenovo-ideapad-110-15ISK:~$
Solution
Enter passwd:
sudo vim /etc/passwd
We can see that:
root:x:0:0:root:/root:/usr/local/bin/zsh
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
bin:x:2:2:bin:/bin:/usr/sbin/nologin
sys:x:3:3:sys:/dev:/usr/sbin/nologin
sync:x:4:65534:sync:/bin:/bin/sync
games:x:5:60:games:/usr/games:/usr/sbin/nologin
man:x:6:12:man:/var/cache/man:/usr/sbin/nologin
lp:x:7:7:lp:/var/spool/lpd:/usr/sbin/nologin
mail:x:8:8:mail:/var/mail:/usr/sbin/nologin
news:x:9:9:news:/var/spool/news:/usr/sbin/nologin
uucp:x:10:10:uucp:/var/spool/uucp:/usr/sbin/nologin
proxy:x:13:13:proxy:/bin:/usr/sbin/nologin
www-data:x:33:33:www-data:/var/www:/usr/sbin/nologin
backup:x:34:34:backup:/var/backups:/usr/sbin/nologin
list:x:38:38:Mailing List Manager:/var/list:/usr/sbin/nologin
irc:x:39:39:ircd:/var/run/ircd:/usr/sbin/nologin
gnats:x:41:41:Gnats Bug-Reporting System(admin):/var/lib/gnats:/usr/sbin/nologin
nobody:x:65534:65534:nobody:/nonexistent:/usr/sbin/nologin
systemd-timesync:x:100:102:systemd Time Synchronization,,,:/run/systemd:/bin/false
systemd-network:x:101:103:systemd Network Management,,,:/run/systemd/netif:/bin/false
systemd-resolve:x:102:104:systemd Resolver,,,:/run/systemd/resolve:/bin/false
systemd-bus-proxy:x:103:105:systemd Bus Proxy,,,:/run/systemd:/bin/false
syslog:x:104:108::/home/syslog:/bin/false
_ apt:x:105:65534::/nonexistent:/bin/false
messagebus:x:106:110::/var/run/dbus:/bin/false
uuidd:x:107:111::/run/uuidd:/bin/false
lightdm:x:108:114:Light Display Manager:/var/lib/lightdm:/bin/false
whoopsie:x:109:116::/nonexistent:/bin/false
avahi-autoipd:x:110:119:Avahi autoip daemon,,,:/var/lib/avahi-autoipd:/bin/false
avahi:x:111:120:Avahi mDNS daemon,,,:/var/run/avahi-daemon:/bin/false
dnsmasq:x:112:65534:dnsmasq,,,:/var/lib/misc:/bin/false
colord:x:113:123:colord colour management daemon,,,:/var/lib/colord:/bin/false
speech-dispatcher:x:114:29:Speech Dispatcher,,,:/var/run/speech-dispatcher:/bin/false
hplip:x:115:7:HPLIP system user,,,:/var/run/hplip:/bin/false
kernoops:x:116:65534:Kernel Oops Tracking Daemon,,,:/:/bin/false
pulse:x:117:124:PulseAudio daemon,,,:/var/run/pulse:/bin/false
rtkit:x:118:126:RealtimeKit,,,:/proc:/bin/false
saned:x:119:127::/var/lib/saned:/bin/false
usbmux:x:120:46:usbmux daemon,,,:/var/lib/usbmux:/bin/false
shanlei: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:
Change the /usr/local/bin/bash on the first line to /usr/local/bin/zsh, this is for the root user:
root:x:0:0:root:/root:/usr/local/bin/bash
Change the last line of /bin/bash to /bin/zsh, this should be the login user name + computer name of each computer:
shanlei:x:1000:1000:shanlei,,,:/home/shanlei:/bin/bash
Save and exit, restart the shell, switch root permissions, and find that there are no files or directories in /usr/local/bin/bash
Check the bash installation location:
shanlei@shanlei-Lenovo-ideapad-110-15ISK:~$ whereis bash
bash:/bin/bash /etc/bash.bashrc /usr/share/man/man1/bash.1.gz
shanlei@shanlei-Lenovo-ideapad-110-15ISK:~$
Found that the execution file of bash is in /bin/bash, so I re-modified the first line of the /etc/passwd file:
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:~$ su -
password:
root@shanlei-Lenovo-ideapad-110-15ISK:~#
Success~
——– Beautiful dividing line——–
There are two other ways to modify the default shell of ubuntu:
sudo ln -s /bin/bash /bin/shsudo dpkg-reconfigure dash, pop up an option, set "dash as default shell" and select no.How can I check which shells are installed on my machine?
shanlei@shanlei-Lenovo-ideapad-110-15ISK:~$ cat /etc/shells
# /etc/shells: valid login shells
/bin/sh
/bin/dash
/bin/bash
/bin/rbash
shanlei@shanlei-Lenovo-ideapad-110-15ISK:~$
How can I check which shell I am currently using? (Note that SHELL must be capitalized!)
shanlei@shanlei-Lenovo-ideapad-110-15ISK:~$ echo $SHELL
/bin/bash
shanlei@shanlei-Lenovo-ideapad-110-15ISK:~$
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, and the bash or zsh we use only starts a bash or zsh interpreter program, and does not change the big environment. If you want to change the big environment , Must use chsh
to sum up
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