diff --git a/en_US.ISO8859-1/books/handbook/basics/chapter.sgml b/en_US.ISO8859-1/books/handbook/basics/chapter.sgml index fb2261f2b2..a430b5584a 100644 --- a/en_US.ISO8859-1/books/handbook/basics/chapter.sgml +++ b/en_US.ISO8859-1/books/handbook/basics/chapter.sgml @@ -1,536 +1,536 @@ Unix Basics Synopsis Rewritten by Chris Shumway cshumway@cdrom.com, 10 Mar 2000. The following chapter will cover the basic commands and functionality of the FreeBSD operating system. If you are new to FreeBSD, you will definitely want to read through this chapter before asking for help. Permissions FreeBSD, having its history rooted in BSD UNIX, has its fundamentals based on several key UNIX concepts. The first, and most pronounced, is that FreeBSD is a multi-user operating system. The system can handle several users all working simultaneously on completely unrelated tasks. The system is responsible for properly sharing and managing requests for hardware devices, peripherals, memory, and CPU time evenly to each user. Because the system is capable of supporting multiple users, everything the system manages has a set of permissions governing who can read, write, and execute the resource. These permissions are stored as an octet broken into three pieces, one for the owner of the file, one for the group that the file belongs to, and one for everyone else. This numerical representation works like this: Value Permission Directory Listing 0 No read, no write, no execute --- 1 No read, no write, execute --x 2 No read, write, no execute -w- 3 No read, write, execute -wx 4 Read, no write, no execute r-- 5 Read, no write, execute r-x 6 Read, write, no execute rw- 7 Read, write, execute rwx For the long directory listing by ls -l, a column will show a file's permissions for the owner, group, and everyone else. Here's how it is broken up: -rw-r--r-- The first character, from left to right, is a special character that tells if this is a regular file, a directory, a special character or block device, a socket, or any other special pseudo-file device. The next three characters, designated as rw- gives the permissions for the owner of the file. The next three characters, r-- gives the permissions for the group that the file belongs to. The final three characters, r--, gives the permissions for the rest of the world. A dash means that the permission is turned off. In the case of this file, the permissions are set so the owner can read and write to the file, the group can read the file, and the rest of the world can only read the file. According to the table above, the permissions for this file would be 644, where each digit represents the three parts of the file's permission. This is all well and good, but how does the system control permissions on devices? FreeBSD actually treats most hardware devices as a file that programs can open, read, and write data to just like any other file. These special device files are stored on the /dev directory. Directories are also treated as files. They have read, write, and execute permissions. The executable bit for a directory has a slightly different meaning than that of files. When a directory is marked executable, it means it can be searched into, for example, a directory listing can be done in that directory. There are more to permissions, but they are primarily used in special circumstances such as setuid binaries and sticky directories. If you want more information on file permissions and how to set them, be sure to look at the &man.chmod.1; man page. Directory Structures Since FreeBSD uses its file systems to determine many fundamental system operations, the hierarchy of the file system is extremely important. Due to the fact that the &man.hier.7; man page provides a complete description of the directory structure, it will not be duplicated here. Please read &man.hier.7; for more information. Of significant importance is the root of all directories, the / directory. This directory is the first directory mounted at boot time and it contains the base system necessary at boot time. The root directory also contains mount points for every other file system that you want to mount. A mount point is a directory where additional file systems can be grafted onto the root file system. Standard mount points include /usr, /var, /mnt, and /cdrom. These directories are usually referenced to entries in the file /etc/fstab. /etc/fstab is a table of various file systems and mount points for reference by the system. Most of the file systems in /etc/fstab are mounted automatically at boot time from the script &man.rc.8; unless they contain the option. Consult the &man.fstab.5; manual page for more information on the format of the /etc/fstab file and the options it contains. Shells In FreeBSD, a lot of everyday work is done in a command line interface called a shell. A shell's main job is to take commands from the input channel and execute them. A lot of shells also have built in functions to help everyday tasks such a file management, - file globing, command line editing, command mar-cos, and environment + file globing, command line editing, command macros, and environment variables. FreeBSD comes with a set of shells, such as sh, the Bourne Shell, and csh, the C-shell. Many other shells are available from the FreeBSD Ports Collection that have much more power, such as tcsh and bash. Which shell do you use? It is really a matter of taste. If you are a C programmer you might feel more comfortable with a C-like shell such as tcsh. If you've come from Linux or are new to a UNIX command line interface you might try bash. The point is that each shell has unique properties that may or may not work with your preferred working environment, and that you have a choice of what shell to use. One common feature in a shell is file-name completion. Given the typing of the first few letters of a command or filename, you can usually have the shell automatically complete the rest of the command or filename by hitting the TAB key on the keyboard. Here is an example. I have two files called foobar and foo.bar. I want to delete foo.bar. So what I would type on the keyboard is: rm fo[TAB].[TAB]. The shell would print out rm foo[BEEP].bar. The [BEEP] is the console bell, which is the shell telling me it was unable to totally complete the filename because there is more than one match. Both foobar and foo.bar start with fo, but it was able to complete to foo. Once I typed in ., then hit TAB again, the shell was able to fill in the rest of the filename for me. Another function of the shell is environment variables. Environment variables are a variable key pair stored in the shell's environment space. This space can be read by any program invoked by the shell, and thus contains a lot of program configuration. Here is a list of common environment variables and what they mean: Variable Description USER Current logged in user's name. PATH Colon separated list of directories to search for binaries. DISPLAY Network name of the X11 display to connect to, if available. SHELL The current shell. TERM The name of the user's terminal. Used to determine the capabilities of the terminal. TERMCAP Database entry of the terminal escape codes to perform various terminal functions. OSTYPE Type of operating system. E.g., FreeBSD. MACHTYPE The CPU architecture that the system is running on. EDITOR The user's preferred text editor. PAGER The user's preferred text pager. MANPATH Colon separated list of directories to search for manual pages. To view or set an environment variable differs somewhat from shell to shell. For example, in the C-Style shells such as tcsh and csh, you would use setenv to set and view environment variables. Under Bourne shells such as sh and bash, you would use set and export to view and set your current environment variables. For example, to set or modify the EDITOR environment variable, under csh or tcsh a command like this would set EDITOR to /usr/local/bin/emacs: setenv EDITOR /usr/local/bin/emacs Under Bourne shells: export EDITOR="/usr/local/bin/emacs" You can also make most shells expand the environment variable by placing a $ character in front of it on the command line. For example, echo $TERM would print out whatever $TERM is set to, because the shell expands $TERM and passes it on to echo. Shells treat a lot of special characters, called meta-characters as special representations of data. The most common one is the * character, which represents any number of characters in a filename. These special meta-characters can be used to do file name globing. For example, typing in echo * is almost the same as typing in ls because the shell takes all the files that match * and puts them on the command line for echo to see. To prevent the shell from interpreting these special characters, they can be escaped from the shell by putting a backslash (\) character in front of them. echo $TERM prints whatever your terminal is set to. echo \$TERM prints $TERM as is. Changing your shell The easiest way to change your shell is to use the chsh command. Running chsh will place you into the editor that is in your EDITOR environment variable; if it is not set, you will be placed in vi. Change the “Shell:” line accordingly. You can also give chsh the option; this will set your shell for you, without requiring you to enter an editor. For example, if you wanted to change your shell to bash, the following should do the trick: &prompt.user; chsh -s /usr/local/bin/bash Running chsh with no parameters and editing the shell from there would work also. The shell that you wish to use must be present in the /etc/shells file. If you have installed a shell from the ports collection, then this should have been done for you already. If you installed the shell by hand, you must do this. For example, if you installed bash by hand and placed it into /usr/local/bin, you would want to: &prompt.root; echo "/usr/local/bin/bash" >> /etc/shells Then rerun chsh. Text Editors A lot of configuration in FreeBSD is done by editing a text file. Because of this, it would be a good idea to become familiar with a text editor. FreeBSD comes with a few as part of the base system, and many more are available in the ports collection. The easiest and simplest editor to learn is an editor called ee, which stands for easy editor. To start ee, one would type at the command line ee filename where filename is the name of the file to be edited. For example, to edit /etc/rc.conf, type in ee /etc/rc.conf. Once inside of ee, all of the commands for manipulating the editor's functions are listed at the top of the display. The caret ^ character means the control key on the keyboard, so ^e expands to pressing the control key plus the letter e. To leave ee, hit the escape key, then choose leave editor. The editor will prompt you to save any changes if the file has been modified. FreeBSD also comes with more powerful text editors such as vi as part of the base system, and emacs and vim as part of the FreeBSD ports collection. These editors offer much more functionality and power at the expense of being a little more complicated to learn. However if you plan on doing a lot of text editing, learning a more powerful editor such as vim or emacs will save you much more time in the long run. For more information... Manual pages The most comprehensive documentation on FreeBSD is in the form of man pages. Nearly every program on the system comes with a short reference manual explaining the basic operation and various arguments. These manuals can be viewed with the man command. Use of the man command is simple: &prompt.user; man command command is the name of the command you wish to learn about. For example, to learn more about ls command type: &prompt.user; man ls The online manual is divided up into numbered sections: User commands. System calls and error numbers. Functions in the C libraries. Device drivers. File formats. Games and other diversions. Miscellaneous information. System maintenance and operation commands. Kernel developers. In some cases, the same topic may appear in more than one section of the online manual. For example, there is a chmod user command and a chmod() system call. In this case, you can tell the man command which one you want by specifying the section: &prompt.user; man 1 chmod This will display the manual page for the user command chmod. References to a particular section of the online manual are traditionally placed in parenthesis in written documentation, so &man.chmod.1; refers to the chmod user command and &man.chmod.2; refers to the system call. This is fine if you know the name of the command and simply wish to know how to use it, but what if you cannot recall the command name? You can use man to search for keywords in the command descriptions by using the switch: &prompt.user; man -k mail With this command you will be presented with a list of commands that have the keyword “mail” in their descriptions. This is actually functionally equivalent to using the apropos command. So, you are looking at all those fancy commands in /usr/bin but do not have the faintest idea what most of them actually do? Simply do a &prompt.user; cd /usr/bin; man -f * or &prompt.user; cd /usr/bin; whatis * which does the same thing. GNU Info Files FreeBSD includes many applications and utilities produced by the Free Software Foundation (FSF). In addition to man pages, these programs come with more extensive hypertext documents called info files which can be viewed with the info command or, if you installed emacs, the info mode of emacs. To use the &man.info.1; command, simply type: &prompt.user; info For a brief introduction, type h. For a quick command reference, type ?. diff --git a/en_US.ISO_8859-1/books/handbook/basics/chapter.sgml b/en_US.ISO_8859-1/books/handbook/basics/chapter.sgml index fb2261f2b2..a430b5584a 100644 --- a/en_US.ISO_8859-1/books/handbook/basics/chapter.sgml +++ b/en_US.ISO_8859-1/books/handbook/basics/chapter.sgml @@ -1,536 +1,536 @@ Unix Basics Synopsis Rewritten by Chris Shumway cshumway@cdrom.com, 10 Mar 2000. The following chapter will cover the basic commands and functionality of the FreeBSD operating system. If you are new to FreeBSD, you will definitely want to read through this chapter before asking for help. Permissions FreeBSD, having its history rooted in BSD UNIX, has its fundamentals based on several key UNIX concepts. The first, and most pronounced, is that FreeBSD is a multi-user operating system. The system can handle several users all working simultaneously on completely unrelated tasks. The system is responsible for properly sharing and managing requests for hardware devices, peripherals, memory, and CPU time evenly to each user. Because the system is capable of supporting multiple users, everything the system manages has a set of permissions governing who can read, write, and execute the resource. These permissions are stored as an octet broken into three pieces, one for the owner of the file, one for the group that the file belongs to, and one for everyone else. This numerical representation works like this: Value Permission Directory Listing 0 No read, no write, no execute --- 1 No read, no write, execute --x 2 No read, write, no execute -w- 3 No read, write, execute -wx 4 Read, no write, no execute r-- 5 Read, no write, execute r-x 6 Read, write, no execute rw- 7 Read, write, execute rwx For the long directory listing by ls -l, a column will show a file's permissions for the owner, group, and everyone else. Here's how it is broken up: -rw-r--r-- The first character, from left to right, is a special character that tells if this is a regular file, a directory, a special character or block device, a socket, or any other special pseudo-file device. The next three characters, designated as rw- gives the permissions for the owner of the file. The next three characters, r-- gives the permissions for the group that the file belongs to. The final three characters, r--, gives the permissions for the rest of the world. A dash means that the permission is turned off. In the case of this file, the permissions are set so the owner can read and write to the file, the group can read the file, and the rest of the world can only read the file. According to the table above, the permissions for this file would be 644, where each digit represents the three parts of the file's permission. This is all well and good, but how does the system control permissions on devices? FreeBSD actually treats most hardware devices as a file that programs can open, read, and write data to just like any other file. These special device files are stored on the /dev directory. Directories are also treated as files. They have read, write, and execute permissions. The executable bit for a directory has a slightly different meaning than that of files. When a directory is marked executable, it means it can be searched into, for example, a directory listing can be done in that directory. There are more to permissions, but they are primarily used in special circumstances such as setuid binaries and sticky directories. If you want more information on file permissions and how to set them, be sure to look at the &man.chmod.1; man page. Directory Structures Since FreeBSD uses its file systems to determine many fundamental system operations, the hierarchy of the file system is extremely important. Due to the fact that the &man.hier.7; man page provides a complete description of the directory structure, it will not be duplicated here. Please read &man.hier.7; for more information. Of significant importance is the root of all directories, the / directory. This directory is the first directory mounted at boot time and it contains the base system necessary at boot time. The root directory also contains mount points for every other file system that you want to mount. A mount point is a directory where additional file systems can be grafted onto the root file system. Standard mount points include /usr, /var, /mnt, and /cdrom. These directories are usually referenced to entries in the file /etc/fstab. /etc/fstab is a table of various file systems and mount points for reference by the system. Most of the file systems in /etc/fstab are mounted automatically at boot time from the script &man.rc.8; unless they contain the option. Consult the &man.fstab.5; manual page for more information on the format of the /etc/fstab file and the options it contains. Shells In FreeBSD, a lot of everyday work is done in a command line interface called a shell. A shell's main job is to take commands from the input channel and execute them. A lot of shells also have built in functions to help everyday tasks such a file management, - file globing, command line editing, command mar-cos, and environment + file globing, command line editing, command macros, and environment variables. FreeBSD comes with a set of shells, such as sh, the Bourne Shell, and csh, the C-shell. Many other shells are available from the FreeBSD Ports Collection that have much more power, such as tcsh and bash. Which shell do you use? It is really a matter of taste. If you are a C programmer you might feel more comfortable with a C-like shell such as tcsh. If you've come from Linux or are new to a UNIX command line interface you might try bash. The point is that each shell has unique properties that may or may not work with your preferred working environment, and that you have a choice of what shell to use. One common feature in a shell is file-name completion. Given the typing of the first few letters of a command or filename, you can usually have the shell automatically complete the rest of the command or filename by hitting the TAB key on the keyboard. Here is an example. I have two files called foobar and foo.bar. I want to delete foo.bar. So what I would type on the keyboard is: rm fo[TAB].[TAB]. The shell would print out rm foo[BEEP].bar. The [BEEP] is the console bell, which is the shell telling me it was unable to totally complete the filename because there is more than one match. Both foobar and foo.bar start with fo, but it was able to complete to foo. Once I typed in ., then hit TAB again, the shell was able to fill in the rest of the filename for me. Another function of the shell is environment variables. Environment variables are a variable key pair stored in the shell's environment space. This space can be read by any program invoked by the shell, and thus contains a lot of program configuration. Here is a list of common environment variables and what they mean: Variable Description USER Current logged in user's name. PATH Colon separated list of directories to search for binaries. DISPLAY Network name of the X11 display to connect to, if available. SHELL The current shell. TERM The name of the user's terminal. Used to determine the capabilities of the terminal. TERMCAP Database entry of the terminal escape codes to perform various terminal functions. OSTYPE Type of operating system. E.g., FreeBSD. MACHTYPE The CPU architecture that the system is running on. EDITOR The user's preferred text editor. PAGER The user's preferred text pager. MANPATH Colon separated list of directories to search for manual pages. To view or set an environment variable differs somewhat from shell to shell. For example, in the C-Style shells such as tcsh and csh, you would use setenv to set and view environment variables. Under Bourne shells such as sh and bash, you would use set and export to view and set your current environment variables. For example, to set or modify the EDITOR environment variable, under csh or tcsh a command like this would set EDITOR to /usr/local/bin/emacs: setenv EDITOR /usr/local/bin/emacs Under Bourne shells: export EDITOR="/usr/local/bin/emacs" You can also make most shells expand the environment variable by placing a $ character in front of it on the command line. For example, echo $TERM would print out whatever $TERM is set to, because the shell expands $TERM and passes it on to echo. Shells treat a lot of special characters, called meta-characters as special representations of data. The most common one is the * character, which represents any number of characters in a filename. These special meta-characters can be used to do file name globing. For example, typing in echo * is almost the same as typing in ls because the shell takes all the files that match * and puts them on the command line for echo to see. To prevent the shell from interpreting these special characters, they can be escaped from the shell by putting a backslash (\) character in front of them. echo $TERM prints whatever your terminal is set to. echo \$TERM prints $TERM as is. Changing your shell The easiest way to change your shell is to use the chsh command. Running chsh will place you into the editor that is in your EDITOR environment variable; if it is not set, you will be placed in vi. Change the “Shell:” line accordingly. You can also give chsh the option; this will set your shell for you, without requiring you to enter an editor. For example, if you wanted to change your shell to bash, the following should do the trick: &prompt.user; chsh -s /usr/local/bin/bash Running chsh with no parameters and editing the shell from there would work also. The shell that you wish to use must be present in the /etc/shells file. If you have installed a shell from the ports collection, then this should have been done for you already. If you installed the shell by hand, you must do this. For example, if you installed bash by hand and placed it into /usr/local/bin, you would want to: &prompt.root; echo "/usr/local/bin/bash" >> /etc/shells Then rerun chsh. Text Editors A lot of configuration in FreeBSD is done by editing a text file. Because of this, it would be a good idea to become familiar with a text editor. FreeBSD comes with a few as part of the base system, and many more are available in the ports collection. The easiest and simplest editor to learn is an editor called ee, which stands for easy editor. To start ee, one would type at the command line ee filename where filename is the name of the file to be edited. For example, to edit /etc/rc.conf, type in ee /etc/rc.conf. Once inside of ee, all of the commands for manipulating the editor's functions are listed at the top of the display. The caret ^ character means the control key on the keyboard, so ^e expands to pressing the control key plus the letter e. To leave ee, hit the escape key, then choose leave editor. The editor will prompt you to save any changes if the file has been modified. FreeBSD also comes with more powerful text editors such as vi as part of the base system, and emacs and vim as part of the FreeBSD ports collection. These editors offer much more functionality and power at the expense of being a little more complicated to learn. However if you plan on doing a lot of text editing, learning a more powerful editor such as vim or emacs will save you much more time in the long run. For more information... Manual pages The most comprehensive documentation on FreeBSD is in the form of man pages. Nearly every program on the system comes with a short reference manual explaining the basic operation and various arguments. These manuals can be viewed with the man command. Use of the man command is simple: &prompt.user; man command command is the name of the command you wish to learn about. For example, to learn more about ls command type: &prompt.user; man ls The online manual is divided up into numbered sections: User commands. System calls and error numbers. Functions in the C libraries. Device drivers. File formats. Games and other diversions. Miscellaneous information. System maintenance and operation commands. Kernel developers. In some cases, the same topic may appear in more than one section of the online manual. For example, there is a chmod user command and a chmod() system call. In this case, you can tell the man command which one you want by specifying the section: &prompt.user; man 1 chmod This will display the manual page for the user command chmod. References to a particular section of the online manual are traditionally placed in parenthesis in written documentation, so &man.chmod.1; refers to the chmod user command and &man.chmod.2; refers to the system call. This is fine if you know the name of the command and simply wish to know how to use it, but what if you cannot recall the command name? You can use man to search for keywords in the command descriptions by using the switch: &prompt.user; man -k mail With this command you will be presented with a list of commands that have the keyword “mail” in their descriptions. This is actually functionally equivalent to using the apropos command. So, you are looking at all those fancy commands in /usr/bin but do not have the faintest idea what most of them actually do? Simply do a &prompt.user; cd /usr/bin; man -f * or &prompt.user; cd /usr/bin; whatis * which does the same thing. GNU Info Files FreeBSD includes many applications and utilities produced by the Free Software Foundation (FSF). In addition to man pages, these programs come with more extensive hypertext documents called info files which can be viewed with the info command or, if you installed emacs, the info mode of emacs. To use the &man.info.1; command, simply type: &prompt.user; info For a brief introduction, type h. For a quick command reference, type ?.