I tried to install ksh, but not able to.
ubuntu@shin-instance:~$ ksh --version
Command 'ksh' not found, but can be installed with:
sudo apt install ksh # version 2020.0.0-5, or
sudo apt install ksh93 # version 93u+20120801-7
sudo apt install mksh # version 58-1
ubuntu@shin-instance:~$ sudo apt install ksh
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following additional packages will be installed:
binfmt-support
The following NEW packages will be installed:
binfmt-support ksh
0 upgraded, 2 newly installed, 0 to remove and 50 not upgraded.
Need to get 856 kB of archives.
After this operation, 3046 kB of additional disk space will be used.
Do you want to continue? [Y/n] Y
Err:1 http://archive.ubuntu.com/ubuntu focal/universe amd64 binfmt-support amd64 2.2.0-2
Temporary failure resolving 'archive.ubuntu.com'
Err:2 http://archive.ubuntu.com/ubuntu focal/universe amd64 ksh amd64 2020.0.0-5
Temporary failure resolving 'archive.ubuntu.com'
E: Failed to fetch http://archive.ubuntu.com/ubuntu/pool/universe/b/binfmt-support/binfmt-support_2.2.0-2_amd64.deb Temporary failure resolving 'archive.ubuntu.com'
E: Failed to fetch http://archive.ubuntu.com/ubuntu/pool/universe/k/ksh/ksh_2020.0.0-5_amd64.deb Temporary failure resolving 'archive.ubuntu.com'
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?
ubuntu@shin-instance:~$ apt-get 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)
What am I doing wrong? How can I install ksh?