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Medium 9780596008956

6. Key Management and Agents

Daniel J. Barrett O'Reilly Media ePub

Your SSH private key is a precious thing. When you use public-key authentication, your key proves your identity to SSH servers. We've encountered several programs related to keys:

Creates key pairs

Holds private keys in memory, saving you from typing your passphrase repeatedly

Loads private keys into the agent

However, we haven't gone into much depth, covering only the most basic operations with keys. Now it's time to examine these concepts and programs in detail.

We begin with an overview of SSH identities and the keys that represent them. After that, we thoroughly cover SSH agents and their many features. Finally, we extol the virtues of having multiple SSH identities. If you've been getting by with a single key and only light agent use, we have a lot of cool stuff in store for you. Figure 6-1 summarizes the role of key management in the overall configuration process.

This chapter is the first in a sequence on advanced SSH for end users, as opposed to system administrators. Once you've covered key management in this chapter, we'll take you through client configuration, server configuration, and forwarding in Chapters 7-9.

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Medium 9781607320760


David Robertson University Press of Colorado ePub

FEW HISTORIC MINING TOWNS IN THE UNITED STATES ARE PLAGUED BY MORE severe environmental problems than Picher, Oklahoma. In fact, when the Environmental Protection Agency (EPA) compiled its initial list of Superfund sites in 1983, the community was designated as one of the agency’s highest priority cleanup areas. At the time, the environmental problems afflicting Picher were considered more serious than those at Love Canal, the EPA’s most infamous hazardous waste site. Unlike its ill-famed contemporary, however, many of Picher’s environmental hazards remain uncontrolled more than two decades later. Named after the stream that runs through the Picher area, the Tar Creek Superfund Site extends over forty square miles. It is one of the oldest and most costly Superfund sites in the nation.1

In the early twentieth century, Picher was the largest mining town in the Tri-State Mining District, once the world’s most productive lead and zinc mining field. Ore was discovered in the Picher region in 1914 and within three years, the settlement’s population exceeded 20,000. A quintessential boomtown, Picher captivated its earliest visitors with its remarkable growth. Mines were opening at a feverish pace and outsiders marveled at how quickly the mine derrick and ore mill, unquestionable symbols of prosperity, had come to dominate the prairie landscape. Community accolades quickly turned to antipathy, however, after the novelty of the mineral discovery faded. The intrusive nature of industrial development, the lack of basic civic amenities, and Picher’s ramshackle appearance were impossible to ignore, and although some sympathized with the plight of its residents, most simply voiced disdain for the community. This external perceptual legacy is one Picher has found difficult to discard. The last of Picher’s mines closed more than thirty years ago, but consistent with the mining imaginary, most outsiders still view the town as a hopelessly despoiled place.2

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Medium 9780819874917

VIII Thou shalt close your eyes. Better that you have no idea that I have no idea what I’m doing.

Leigh, Britt Pauline Books and Media ePub


The scene at home is epic. Thundery clouds blow in at the back window, making everything even gloomier. Mom and Dad are standing, yelling, waving hands. I sit at the dinner table, focusing on the blustery afternoon beyond their faces.

Mom rests a hip on the barstool chair near the kitchen ledge. “Now, Gloria Jean. You’re not going to get away without talking about this. Just what is going on with you?”

“Mrs. Gomez told you what happened.” I don’t look at her.

She swivels my chair with her foot so I have to face her. “I want to hear it from you.”

I let my top half collapse onto the kitchen table. I let my stringy hair fall around my face. Maybe Mom will calm down and stroke it. I mumble into my elbow. “I walked to that little shopping plaza on Pelton, went to the drugstore to buy some new lip gloss, and then got a panini at The Book Nook. I just wanted some space.” Without looking up, I fish around in my pocket for the Joie de Vive and set it on the table. It kinda doesn’t make sense for me to have it now.

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Medium 9781576756300

The Wrinkle

Thomas Crum Berrett-Koehler Publishers ePub

He probably never would have looked at his reflection at all, if it hadn’t been for something his daughter said. He would have done what he usually did—go downstairs, get on his computer, and wrestle with deadlines and dilemmas. But tonight, while he was tucking her into bed, Angus noticed Sierra looking at him intently.

“Why do you have that big line on your face, Daddy?”

“What big line?”

“This big line here,” she said, tracing with her finger a line on his brow that extended down between his eyes.

“I guess it’s from worrying too much,” was Angus’s truthful reply.

“What are you going to do?” his daughter persisted.

“I’m not sure.”

He kissed her good night and reached to turn off the light.

“When I’m not sure of something I just ask my teacher.”

“That’s a good idea, Sierra. Now, go to sleep,” he said, closing her bedroom door.

“And my teacher says the answers are always there, Daddy,” he heard her call out. “You just have to look for them.”

That was when he caught his reflection in the hallway mirror.

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Medium 9781937538347

Climate Scientists: Our Modern-Day Prophets

Peter Essick Rocky Nook-IPS ePub

The final segment of the climate change story was called Now What? The idea was to look at scientific research that was being done to predict what might happen in the future. The obvious way to do this was to input temperature data from locations around the world into computer models that would project future conditions. This takes huge amounts of computer memory, and only in recent years with the advent of the supercomputer could reliable projections be made. The resulting projections do not bode well for us. We should be paying attention to the figures, which predict a harrowing future if we continue with business as usual. I was able to photograph a supercomputer at the University of Texas. It had a room with a set of large monitors where you could see the results in visual displays.

My main goal was to photograph scientists doing experiments in the field, but many of the scientists did most of their important work at computers inside offices. However, by reading articles in science and nature magazines, I discovered some scientists working in the new field of paleoclimatology. Paleoclimatologists piece together what the climate was like in years past to predict what might occur in today’s conditions. They have discovered that ice cores, tree rings, and stalagmites all contain signatures within them that have recorded what the climate was like as they were formed.

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