Fix typos

01/intro-to-sysadmin.tex

@@ -192,7 +192,7 @@ \section{What exactly does a System Administrator do?}
 And therein lies the bug: \verb+less(1)+ was invoked
 by the super user, it would check the permissions on
 the file \verb+/root/.lesshst+, follow the redirection
-to \verb+/dev/null+ find that they're not \verb+0600+
+to \verb+/dev/null+, find that they're not \verb+0600+
 and call \verb+chmod(2)+, yielding and
 unreadable/unwritable \verb+/dev/null+.  We were able
 to confirm this behaviour and identified a code change
@@ -1032,7 +1032,7 @@ \section{The Future of System Administration}
 The System Adminstrator's job definition is diverse,
 and so is the rather significant change the profession
 has undergone over the years.  Gone are the days of
-shuffling punch cards, of cycling magentic tapes, of
+shuffling punch cards, of cycling magnetic tapes, of
 connecting your dumb terminals using RS-232 serial
 connections, of stringing ribbon cables inside large
 computer cases... or are they?

03/documentation-techniques.tex

@@ -711,7 +711,7 @@ \section{Formats}
 into language, then you have likely not fully
 understood the problem.  Use illustrations as {\em
 supplementary}, not {\em instead of} information.
-Text ought to be your primary content: it can can
+Text ought to be your primary content: it can
 easily be skimmed, indexed and searched, glanced
 through in a matter of seconds, and parts of a
 paragraph be re-read with ease; a screencast or video,

04/filesystems-and-storage-models.tex

@@ -57,12 +57,12 @@ \section{Introduction}
 
 Available storage space is, despite rapidly falling
 prices for traditional hard disk drives, a scarce
-resource\footnote{We will take a closer look a the
+resource\footnote{We will take a closer look at the
 {\em Total Cost of Ownership\index{Total Cost of
 Ownership}} of a hard drive in Chapter
 \ref{chap:backup}.  Suffice it to say that the
 purchase price of the storage device itself is only a
-fraction.}.  The quote a the beginning of this chapter
+fraction.}.  The quote at the beginning of this chapter
 is rather apt: no matter how much disk space we make
 available to our users, we will eventually run out and
 need to expand.  In order to accommodate the
@@ -2036,7 +2036,7 @@ \section{File System Layout}
 
 File names may contain any character except for this
 separator or the {\em NUL} character ({\tt
-\textbackslash0}), used in the the C programming
+\textbackslash0}), used in the C programming
 language to terminate a string.\footnote{It is a
 common mistake to assume that a file name contains
 only printable characters.  The Unix system does not

05/software-installation-and-package-management.tex

@@ -226,7 +226,7 @@ \subsection{Up and down the software stack}
 		see Chapter \ref{file systems:storage-models:dividing-and-combining-disks:partitions}
 	\item execution of a secondary or second-stage boot loader --
 		\index{boot loader!second-stage} a small program allowing
-		the user to interactively choose an operating systems or
+		the user to interactively choose an operating system or
 		kernel to boot; examples include GRUB\index{GRUB} (Figure
 		\ref{fig:software-installation:grub}) or
 		{\tt boot(8)}\index{\tt boot(8)}
@@ -577,7 +577,7 @@ \subsection{Operating System vs. System Software vs. Third Party Software}
 As different OS providers disagree on what components
 should be part of their final product, it becomes very
 difficult to declare a software package to belong into
-any one of the cateogries we've defined.  However,
+any one of the categories we've defined.  However,
 most system administrators ultimately develop an
 instinctive idea of what should or should not be
 considered {\em essential}, what can and cannot be
@@ -1009,7 +1009,7 @@ \subsection{OS Installation Overview}
 		state than under normal circumstances, and it is possible
 		to forget to enable or disable a service.  Placing the
 		system into production use without a fresh reboot might
-		lead to unexepcted results when the system is rebooted at
+		lead to unexpected results when the system is rebooted at
 		a later point.
 \end{itemize}
 
@@ -1058,7 +1058,7 @@ \subsection{OS Installation Overview}
 written your own deployment system. Or configuration
 management system.  Or inventory database.  Or
 parallel secure shell to perform tasks across all of
-your host.  Or... \\ [10pt]
+your hosts.  Or... \\ [10pt]
 
 Anyway, the system we wrote was elegant, and it taught
 us a lot about the details of the OS installation
@@ -1264,7 +1264,7 @@ \subsection{OS Installation Details}
 
 Listing \ref{code:netbsd-install} shows the most basic
 steps to perform a minimal OS installation.  It is
-interesting to analyze each of them (and constrast the
+interesting to analyze each of them (and contrast the
 sequence for different operating systems), as doing so
 often illustrates a number of assumptions made about
 the use of the software.  The ease with which an OS
@@ -1782,7 +1782,7 @@ \subsection{Inherent Security Risks}
 this end, they provide the capability for a given
 package to execute an arbitrary shell script provided
 in the package, with the privileges of the invoking
-using -- commonly the superuser.
+user -- commonly the superuser.
 
 In other words, it is important to understand that any
 time we use a package manager to retrieve and install

06/of-users-and-groups.tex

@@ -50,7 +50,7 @@ \section{Introduction}
 in formalizing your access control requirements so
 as to express and apply them using your configuration
 management system\index{Configuration Management}, as
-we will discuss in the Chapter
+we will discuss in Chapter
 \ref{chap:configuration-management}.
 
 As one of our Pillars of Exceptional System Design,
@@ -204,7 +204,7 @@ \section{Types of Users}
 sake, however, we should mention that more modern
 access semantics, such as {\em mandatory access
 controls} (MAC), {\em role-based access controls}
-(RBAC), or POSIX ``capabilities''  can been added,
+(RBAC), or POSIX ``capabilities''  can be added,
 albeit at the cost of increased complexity.}
 
 Reviewing these access rules, we can identify mappings
@@ -667,7 +667,7 @@ \subsection{The Problem with Passwords}
 access is granted, and you are logged in.  From that
 moment on, regular Unix semantics and permissions will
 apply to decide whether or not access to a given
-resources (e.g. the ability to write to a file) is
+resource (e.g. the ability to write to a file) is
 granted.
 
 Passwords are an easy and convenient way for users to
@@ -721,7 +721,7 @@ \subsection{The Problem with Passwords}
 \gls{ldap}\index{LDAP}} is an example of this
 approach.  However, it should be noted that the
 benefits of a central location of this information
-carries a certain prize, as well: if the host(s)
+carries a certain price, as well: if the host(s)
 providing this service becomes unavailable, thousands
 of hosts can become unusable or see debilitating
 errors.  This problem can of course be defined in a
@@ -740,7 +740,7 @@ \subsection{The Problem with Passwords}
 most people are rather terrible at remembering complex
 passwords (which are harder for computers to crack)
 and hence tend to use and reuse across different sites
-a small set of a simple passwords This means that
+a small set of simple passwords.  This means that
 accounts on your systems may get compromised by
 password leaks in another, completely different and
 independent environment!
@@ -827,7 +827,7 @@ \subsection{Sharing {\tt root}}
 protocols allow well-defined control of remote access
 do, for the most part, still follow an all-or-nothing
 access model locally.  The access credentials for the
-privileged accounts on these devices (as example might
+privileged accounts on these devices (an example might
 be the ``enable'' password, used to enter privileged
 mode on a router or switch) need to be managed and
 shared with the same care that a {\tt root} password
@@ -885,7 +885,7 @@ \section{Summary}
 		users in your organization {\em today}, you will
 		eventually grow to a size where this no longer holds.  It
 		is near impossible to later on put in place restrictions
-		on users' privileges, just as it is to anticiapate the
+		on users' privileges, just as it is to anticipate the
 		possibly sudden departure of trusted employees.
 	\item {\em You will always face tradeoffs.}  No matter which
 		authentication mechanism you choose, there are downsides.

07/configuration-management.tex

@@ -248,7 +248,7 @@ \section{Services, not Single Points of Failure}
 \section{Defining Services and Requirements}
 \label{configuration-management:defining-services}
 
-System administrators tend to be very practially
+System administrators tend to be very practically
 oriented and are likely to start out setting up a new
 service by installing the required software to
 evaluate, tune it, change it, adapt it to the needs of
@@ -845,7 +845,7 @@ \subsubsection*{Unknown} The CM may have stopped
 
 Much more challenging for both the CM as well as the
 system administrators in charge are the prevention and
-detection a the last two states, ``deviant'' and
+detection of the last two states, ``deviant'' and
 ``unknown''.  In order to recover and return the
 system back to production, the software needs to be
 able to identify error conditions and determine the
@@ -1087,7 +1087,7 @@ \subsection{Deployment roles}
 shipped to the customers.  In the context of
 configuration management, this might be a service
 definition that has to be verified to not
-inadvertendly break the systems on which is should be
+inadvertently break the systems on which is should be
 deployed, including new releases of the service
 software.
 
@@ -1126,7 +1126,7 @@ \subsubsection*{Development}
 These hosts serve as the playground where all
 prototypes are initially set up as proofs of concept
 before being properly packaged and turned into a
-defined services.  All new changes are initially
+defined service.  All new changes are initially
 developed and tested in this environment.  Hosts in
 this role are often in a state of flux, and it is not
 uncommon for a system administrator to break a service
@@ -1150,7 +1150,7 @@ \subsubsection*{Test}
 configuration management software, and does not cause
 any obvious problems.
 
-In a heterogenous environment it is import to ensure that all major
+In a heterogenous environment it is important to ensure that all major
 operating system versions are represented in this group.
 
 \subsubsection*{Pre-Production}
@@ -1423,7 +1423,7 @@ \subsection{Idempotence and Convergence}
 interruptions on the way from state A to state B.
 Both principles are often fully understood and
 appreciated only after a lot of practical experience
-and a perhaps a few ``interesting'' error scenarios,
+and perhaps a few ``interesting'' error scenarios,
 but try to keep them in mind as you develop and deploy
 your CM solution.
 

09/scalable-tools.tex

@@ -256,7 +256,7 @@ \subsection{Programs}
 initial prototype and rewrite the tool, possibly in
 another language.  Even though it is difficult to
 willingly discard an existing solution into which time
-and effort have gone, this is, after all, the the main
+and effort have gone, this is, after all, the main
 purpose of a {\em prototype}: to allow you to learn
 the details of the problem and to provide a proof of
 concept implementation on which to model your later
@@ -305,7 +305,7 @@ \subsection{Programs}
 across numerous systems.  Without realizing, we may
 have developed a core infrastructure component upon
 which our organization relies.  At this point, the
-software is likely to have advanced to into the stage
+software is likely to have advanced to the stage
 of being a full-featured, self-contained application,
 requiring ongoing maintenance, development and
 support.  We have crossed the boundary from
@@ -372,7 +372,7 @@ \subsection{Software Products}
 approximately 75\% of ongoing maintenance and bug
 fixes!\footnote{System Administrators tend to agree
 that installation and operational maintenance of the
-product make up the remaining 75\%.}
+product make up the remaining 25\%.}
 
 But even though system administrators may well play an
 important role in the design of internal
@@ -432,7 +432,7 @@ \subsection{Software Products}
 \section{Principles of Developing Robust System Tools}
 \label{building-scalable-tools:principles}
 
-A large number of of System Administrators remain --
+A large number of System Administrators remain --
 unconsciously and unintentionally -- stuck in
 ``scripting mode''.  That is, their software reflects
 the mindset and language previously described, and the
@@ -1223,7 +1223,7 @@ \subsection{Of Buses and Windows}
 of this, but often this is not sufficient to help
 somebody else really understand the code and debug it
 in case of an emergency.  For that, you need to
-atually explain your code to your peers, an approach
+actually explain your code to your peers, an approach
 sometimes referred as ``decreasing your Bus
 Factor\index{Bus Factor}'': you should ensure that
 even if you were to suddenly disappear (because, for
@@ -1273,7 +1273,7 @@ \subsection{Of Buses and Windows}
 -- the debate over whether one should use tabs or
 spaces to indent has been ongoing for decades now,
 with no resolution in sight\footnote{Tabs, of course.}
--- but it in the interest of improving the readability
+-- but in the interest of improving the readability
 of your code and making it easier for everyone in the
 organization to easily understand each others
 programs, it is important to follow them all the
@@ -1305,7 +1305,7 @@ \subsection{Code Reviews}
 before code can be committed in a repository, it
 requires somebody else to sign off.  So-called
 ``commit hooks'' in a code repository can enforce this
-by requiring the commit messages to include the works
+by requiring the commit messages to include the words
 ``reviewed by: username''.  In order to allow
 reasonably efficient and agile development, this
 system requires occasional exceptions, and so we do
@@ -1366,7 +1366,7 @@ \section{Additional Guidelines}
 the availability and usefulness of accompanying
 documentation.  The following short guidelines may
 help you conciously consider your own development
-approach and your own tools in copmarison: \\
+approach and your own tools in comparison: \\
 
 {\bf Write meaningful commit messages.}\index{commit
 messages}  As you collaborate on a project with your
@@ -1635,7 +1635,7 @@ \section*{Problems}
 \item
 Review your own interpretation of what makes a
 ``good'' program.  Do you judge a program by how it
-performs alone?  Do you consider a consisten user
+performs alone?  Do you consider a consistent user
 interface, availability of documentation, code
 readability or elegance, etc.?  If the tool works and
 does what you need it to do -- should you pay