pages tagged ssh

Examples of using ssh

Tue, 16 May 2017 23:59:39 +0000

Connect to host via intermediate host

To connect to destination host1 via intermediate host2:

$ ssh -t user2@host2 ssh user1@host1

References

stackexchange thread: How to ssh to a server using another server?

External links

Installing and configuring OpenSSH

Tue, 16 May 2017 23:59:39 +0000

Installing

macOS

Install MacPorts
Install OpenSSH
```
  $ sudo port install OpenSSH
```

Set up password-less `ssh` to remote machines

Create a key if you don't have ~/.ssh/id_rsa.pub
```
  $ ssh-keygen -t rsa
```
Download portable OpenSSH from here if you don't have a ssh-copy-id, then
```
  $ ssh-copy-id -i ~/.ssh/id_rsa.pub username@remoteserver
```
Test password-less ssh
```
  $ssh remoteserver whoami
```

References

Debian Administration: Password-less logins with OpenSSH

Installing and configuring pkgsrc

Sat, 08 Apr 2017 21:30:47 +0000

Intro to pkgsrc

pkgsrc is a package management system for Unix-like operating systems. It supports OS X. Therefore, it's an viable alternative to Homebrew and Macports, which are the most widely used package management systems on Mac computers. I originally became interested in trying pkgsrc because some softwares I would like to install are not available via Homebrew.

Install, configure, manage pkgsrc and software packages in it

Installing and configuring pkgsrc on macOS (64-bit, version 10.9 or later)

The following is based on https://pkgsrc.joyent.com/install-on-osx/.

Copy and paste the lines below to install the 64-bit 10.9+ set.

  BOOTSTRAP_TAR="bootstrap-trunk-x86_64-20170205.tar.gz"
  BOOTSTRAP_SHA="177e0be390b57ef9d7f61511a8169268000693df"

Download the bootstrap kit to the current directory.

  curl -O https://pkgsrc.joyent.com/packages/Darwin/bootstrap/${BOOTSTRAP_TAR}

Verify the SHA1 checksum.

  echo "${BOOTSTRAP_SHA}  ${BOOTSTRAP_TAR}" >check-shasum
  shasum -c check-shasum

Verify PGP signature. This step is optional, and requires gpg.

  curl -O https://pkgsrc.joyent.com/packages/Darwin/bootstrap/${BOOTSTRAP_TAR}.asc
  gpg --recv-keys 0x1F32A9AD
  gpg --verify ${BOOTSTRAP_TAR}{.asc,}

Install bootstrap kit to /opt/pkg
```
  sudo tar -zxpf ${BOOTSTRAP_TAR} -C /
```
Reload PATH/MANPATH (pkgsrc installs /etc/paths.d/10-pkgsrc for new sessions)
```
  eval $(/usr/libexec/path_helper)
```

Installing pkgsrc on Ubuntu Linux

TODO

Installing softwares

There are three ways of installing softwares using pkgsrc:

The most typical method is to build a software from source files, a.k.a. "bootstrapping";
Another possibly easier method is to install and uninstall pre-built softwares using commands pkg_add and pkg_delete, respectively;
Install softwares using the high-level tool pkgin. It's the facsimile of Ubuntu and Debian Linux's apt-get in pkgsrc.

Use pkgsrc to install softwares

Use pkgsrc to install some softwares that Homebrew can't.

Refresh the pkgin database with the latest version
```
  $ sudo pkgin -y update
```

Search for a package. Regular expressions are supported.

  $ pkgin search "^ffmpeg[0-9]$"
  ffmpeg3-3.0.1   Decoding, encoding and streaming software (v3.x)
  ffmpeg2-2.8.6   Decoding, encoding and streaming software (v2.x)
  ffmpeg1-1.2.12  Decoding, encoding and streaming software (v1.x)

Install a package without prompting
```
  $ sudo pkgin -y install ffmpeg3
```
List all available packages
```
  $ pkgin avail
```
Upgrade all out-of-date packages
```
  $ sudo pkgin -y full-upgrade
```
Remove a package
```
  $ sudo pkgin -y remove ffmpeg2
```
Automatically remove orphaned dependencies
```
  $ sudo pkgin -y autoremove
```

Use pkg_* tools to manage packages

See what packages are installed.
```
  $ pkg_info
```

See what package a file belongs to.

  $ pkg_info -Fe /opt/pkg/bin/node
  nodejs-4.4.3

List the contents of a package.

  $ pkg_info -qL nodejs
  /opt/pkg/bin/node
  /opt/pkg/bin/npm
  [...]

Perform an audit of all currently installed packages.

  $ sudo pkg_admin fetch-pkg-vulnerabilities
  $ pkg_admin audit
  Package jasper-1.900.1nb11 has a integer-overflow vulnerability, see http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-3520
  Package samba-3.6.25nb3 has a privilege-escalation vulnerability, see https://www.samba.org/samba/security/CVE-2015-5299.html
  Package tiff-4.0.6 has a arbitrary-memory-access vulnerability, see http://www.securityfocus.com/archive/1/537205
  [...]

Create a binary package from some metadata files and package directory.

  $ pkg_create -B build-info -c comment -d description -f packlist -I /opt/pkg -p files/ -U foo-1.0.tgz

Configuration file `mk.conf` for "bootstrapping"

After running

pkgsrc/bootstrap

it creates a example configuration file ../pkgsrc/bootstrap/work/mk.conf.example:

# Example /usr/pkg/etc/mk.conf file produced by bootstrap-pkgsrc
# Sat Feb  7 20:20:18 PST 2015

.ifdef BSD_PKG_MK   # begin pkgsrc settings

PKGSRC_COMPILER=    clang
CC=         clang
CXX=            clang++
CPP=            ${CC} -E
CLANGBASE=      /usr

PKG_DBDIR=      /var/db/pkg
LOCALBASE=      /usr/pkg
VARBASE=        /var
PKG_TOOLS_BIN=      /usr/pkg/sbin
PKGINFODIR=     info
PKGMANDIR=      man

TOOLS_PLATFORM.awk?=        /usr/pkg/bin/nawk
TOOLS_PLATFORM.sed?=        /usr/pkg/bin/nbsed

.endif          # end pkgsrc settings

Here is a version that is customized and installed at /usr/pkg/etc/mk.conf:

.ifdef BSD_PKG_MK       # begin pkgsrc settings

ABI=                    64
PKGSRC_COMPILER=        clang
CC=                     clang
CXX=                    clang++
CPP=                    ${CC} -E
CLANGBASE=              /usr

PKG_DBDIR=              /usr/pkg/.pkgdb
LOCALBASE=              /usr/pkg
VARBASE=                /var
PKG_TOOLS_BIN=          /usr/pkg/sbin
PKGINFODIR=             info
PKGMANDIR=              man

TOOLS_PLATFORM.awk?=    /usr/pkg/bin/nawk
TOOLS_PLATFORM.sed?=    /usr/pkg/bin/nbsed

MULTILIB_SUPPORTED=     no

PREFER.openssl=         pkgsrc

X11_TYPE=               native
X11BASE=                /opt/X11

.if !empty(PKGPATH:Mmail/mutt-devel)
PKG_OPTIONS.mutt+=      mutt-hcache mutt-smtp ncursesw sasl
.endif

.endif                  # end pkgsrc settings

Uninstalling pkgsrc and softwares installed by it

Delete the following directories:

sudo rm -rf /usr/pkg
sudo rm -rf /var/db/pkg*

and possibly also the source files if you used the first method:

sudo rm -rf /path/to/pkgsrc

References

Wikipedia, Pkgsrc.
Tony Fischetti, The state of package management on macOS, Oct. 14, 2013
pkgsrc: http://pkgsrc.org/
pkgsrc.se: http://pkgsrc.se/
pkgin: http://pkgin.net/
http://www.perkin.org.uk/pages/pkgsrc-binary-packages-for-osx.html
http://www.onthelambda.com/2013/10/14/the-state-of-package-management-on-mac-os-x/
pkgsrc binary packages for Mac OSX.

Permission of .ssh files

Thu, 26 Feb 2015 00:32:53 +0000

A brief note about the file permissions of $HOME/.ssh files:

$ ls -la ~/.ssh
total 136
drwx------   17 meng  _lpoperator    578 Feb  8 11:54 .
drwxr-xr-x+ 115 meng  _lpoperator   3910 Feb 25 16:10 ..
-rw-------    1 meng  _lpoperator   1671 Feb  8 11:54 config
-rw-------    1 meng  _lpoperator   1631 Jan 28 21:55 config~
drwxr-xr-x    4 meng  _lpoperator    136 Oct 27 15:16 git-annex
-rw-------    1 meng  _lpoperator   3243 Jan 28 20:47 id_rsa_work
-rw-r--r--    1 meng  _lpoperator    748 Jan 28 20:47 id_rsa_work.pub
-rw-------    1 meng  _lpoperator   1743 Jan 15  2012 id_rsa_lumengdev
-rw-r--r--    1 meng  _lpoperator    402 Jan 15  2012 id_rsa_lumengdev.pub
-rw-r--r--    1 meng  _lpoperator  10174 Feb 19 10:37 known_hosts
-rw-r--r--    1 meng  _lpoperator   7577 Oct  9 15:29 known_hosts~

$HOME/.ssh folder should have permission 700.
config and private/secret key files id_rsa_XXX should have 600.
known_hosts and public/shared key files id_rsa_XXX.public should have 644. And it's fine to have serveral pairs of private/secret and public/shared key files.

Check the default permissions of `.ssh`

Run ssh <host> will create $HOME/.ssh and $HOME/.ssh/known_hosts file and add an entry for the <host> in it. Running ssh-keygen will create the public/shared and private/secret key pair files: $HOME/.ssh/id_rsa.pub and $HOME/.ssh/id_rsa. Their default permissions are

16:24:06 meng@mycomputer:~/.ssh$ ls -la
total 24
drwx------    5 meng  _lpoperator   170 Feb 25 16:24 .
drwxr-xr-x+ 116 meng  _lpoperator  3944 Feb 25 16:23 ..
-rw-------    1 meng  _lpoperator  1766 Feb 25 16:24 id_rsa
-rw-r--r--    1 meng  _lpoperator   404 Feb 25 16:24 id_rsa.pub
-rw-r--r--    1 meng  _lpoperator   414 Feb 25 16:23 known_hosts
16:24:11 meng@mycomputer:~/.ssh$ ssh -version
OpenSSH_6.2p2, OSSLShim 0.9.8r 8 Dec 2011

References

http://superuser.com/questions/488718/permissions-on-ssh-causing-problems

pages tagged ssh

Examples of using ssh

Connect to host via intermediate host

References

External links

Installing and configuring OpenSSH

Installing

macOS

Set up password-less ssh to remote machines

References

Installing and configuring pkgsrc

Intro to pkgsrc

Install, configure, manage pkgsrc and software packages in it

Installing and configuring pkgsrc on macOS (64-bit, version 10.9 or later)

Installing pkgsrc on Ubuntu Linux

Installing softwares

Use pkgsrc to install softwares

Use pkg_* tools to manage packages

Configuration file mk.conf for "bootstrapping"

Uninstalling pkgsrc and softwares installed by it

References

Permission of .ssh files

Check the default permissions of .ssh

References

Set up password-less `ssh` to remote machines

Configuration file `mk.conf` for "bootstrapping"

Check the default permissions of `.ssh`