May 2017
Beginner
552 pages
28h 47m
English
Content preview from Linux Shell Scripting Cookbook - Third Edition
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Checksum and verification
Checksum programs are used to generate a relatively small unique key from files. We can recalculate the key to confirm that a file has not changed. Files may be modified deliberately (adding a new user changes the password file), accidentally (a data read error from a CD-ROM drive), or maliciously (a virus is inserted). Checksums let us verify that a file contains the data we expect it to.
Checksums are used by backup applications to check whether a file has been modified and needs to be backed up.
Most software distributions also have a checksum file available. Even robust protocols such as TCP can allow a file to be modified in transit. Hence, we need to know whether the received file is the original one or not ...
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
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