Command

|

Linux Kernel: Add support for using a MAX3421E chip as a host driver

This change “Add support for using a MAX3421E chip as a host driver.” (commit 2d53139) in Linux kernel is authored by David Mosberger <davidm [at] egauge.net> on Mon Apr 28 22:14:07 2014 -0600. Description of “Add support for using a MAX3421E chip as a host driver.” The change “Add support for using a MAX3421E chip…

| |

2 Ways of Resetting All Git Submodules in a Git Repository

Git submodule is a nice and convenient mechanism in Git to include the other Git repositories and manage the version/commit used from the submodule Git repository. However, there are cases where we would like “reset” the submodule, such as when we find updating a submodule repository will break the code tree, or merge some updates…

|

Installing R and RStudio Server in Ubuntu Linux

R is a language and environment for statistical computing and graphics, providing a wide variety of statistical and graphical techniques. The R environment is open source software under GPL. R has rich software packages and is widely used for statistical analysis. RStudio Server is an R integrated development environment (IDE) that provides many useful features…

|

Linux Kernel 4.19.70 Release

This post summarizes new features, bugfixes and changes in Linux kernel release 4.19.70. Linux 4.19.70 Release contains 95 changes, patches or new features. In total, there are 101,521 lines of Linux source code changed/added in Linux 4.19.70 release compared to Linux 4.19 release. To view the source code of Linux 4.19.70 kernel release online, please…

| |

Add Inline Comments for Multi-line Command in Bash Script

In Bash script, it is common that multiple small commands run together connected by pipes (|) and the whole command is quite long. For clarity, we may write the command in multiple lines. How to add comments for these long multi-line commands? In Bash, the content after # in a line is the comment. Using…

| |

How to Query Transaction By ID in Hyperledger Fabric 2.0

Querying transaction content out from a blockchain network is a common practice used by common scenarios like exploring the blockchain history or verifying the blockchain transaction content from a known ID. In Hyperledger Fabric, the transaction can be queried using a special system chaincode QSCC (Query System Chaincode) which is for ledger and other Fabric-related…

|

How to Install Hyperledger Fabric 2.0 in Ubuntu 18.04

Hyperledger Fabric is a consortium blockchain system. It’s performance is relatively good and its modular architecture enables it to be usable in many scenarios. Hyperledger Fabric itself has rich documents and samples of test networks. For beginners, deploying a new network for trying and testing still consumes quite some time. In this post, we will…

| |

How to list and start VirtualBox VMs in command line in Linux?

VirtualBox is a nice open source virtual machine software. It works nicely on Linux and is supported by many Linux distros like Ubuntu in their official package repositories, so it is quite easy to set it up on Linux. The VMs can also be managed in command line using the vboxmanage command line tool provided…

|

Generating a Pair of RSA Private and Public Keys in Linux using OpenSSL

RSA (Rivest–Shamir–Adleman) is a widely used public-key cryptosystem that is used for secure communication over the internet. In this post, we will explore how to generate a pair of RSA private and public keys in Linux using the OpenSSL library. Generating a pair of RSA private and public keys in Linux using OpenSSL is a…

How to encrypt a file using openssl on Linux non-interactively?

How to encrypt a file using openssl on Linux non-interactively? The passphrase shall be provied to openssl in a programmatic way instead of requesting the user to input it, so that the command may work in a regular cron job or some batch jobs. To encrypt file file.tgz and store it to file.tgz using aes-256-ebc…

|

How to cat a text file out from a tar archive without having to extracting it?

How to cat a text file out from a compressed tar archive package without having to extracting the whole package? For example, I have a pkg.tar.gz which contains a text file pkg/readme.txt in it. How to cat the pkg/readme.txt file content out? You may use this command to cat out the file content: tar -O…