540 lines
7.3 KiB
HTML
540 lines
7.3 KiB
HTML
<HTML
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><HEAD
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><TITLE
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>Managing users</TITLE
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TITLE="Controlling services"
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>GNU/Linux Command-Line Tools Summary</TH
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><HR
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ALIGN="LEFT"
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WIDTH="100%"></DIV
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><DIV
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CLASS="CHAPTER"
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><H1
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><A
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NAME="MANAGING-USERS"
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></A
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>Chapter 10. Managing users</H1
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><P
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></P
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><DIV
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CLASS="VARIABLELIST"
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><DL
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><DT
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>su username</DT
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><DD
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><P
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><A
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NAME="AEN6246"
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></A
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>(Switch User), change <A
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NAME="AEN6248"
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></A
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>to a different <A
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NAME="AEN6250"
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></A
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>user. </P
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><P
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>Use <SPAN
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CLASS="emphasis"
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><I
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CLASS="EMPHASIS"
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>su -</I
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></SPAN
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> to switch <A
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NAME="AEN6254"
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></A
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>to root or<SPAN
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CLASS="emphasis"
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><I
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CLASS="EMPHASIS"
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> su username</I
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></SPAN
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>, to switch <A
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NAME="AEN6257"
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></A
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>to a different <A
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NAME="AEN6259"
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></A
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>username. </P
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><DIV
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CLASS="TIP"
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><BLOCKQUOTE
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CLASS="TIP"
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><P
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><B
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>Using sudo<A
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NAME="AEN6263"
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></A
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>: </B
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> Its often considered better practice to use the <SPAN
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CLASS="emphasis"
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><I
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CLASS="EMPHASIS"
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>sudo </I
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></SPAN
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>command rather than switch to the root user</P
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><P
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> The <SPAN
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CLASS="emphasis"
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><I
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CLASS="EMPHASIS"
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>sudo</I
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></SPAN
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> command allows you to perform actions as root but logs the actions you take (so you can trace anything that was done to the system by yourself or others). <SPAN
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CLASS="emphasis"
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><I
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CLASS="EMPHASIS"
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>sudo</I
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></SPAN
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> has a very good manual page which provides plenty of information about it.</P
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><P
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> You use sudo similar to how you execute a normal command with sudo prepended to it, for example:</P
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><P
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><PRE
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CLASS="SCREEN"
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> sudo rpm -U myrpm.i386.rpm </PRE
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></P
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><P
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> This would allow you to install a rpm even if you have the correct sudo access </P
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></BLOCKQUOTE
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></DIV
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><P
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>Note that if you want to return <A
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NAME="AEN6275"
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></A
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>to your original <A
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NAME="AEN6277"
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></A
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>user you don't use <SPAN
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CLASS="emphasis"
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><I
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CLASS="EMPHASIS"
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>su</I
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></SPAN
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> again, type <SPAN
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CLASS="emphasis"
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><I
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CLASS="EMPHASIS"
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>exit</I
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></SPAN
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> or press <A
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NAME="AEN6281"
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></A
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>
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<B
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CLASS="KEYCAP"
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>CTRL</B
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>-<B
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CLASS="KEYCAP"
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>D</B
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>
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<A
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NAME="AEN6286"
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></A
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>
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.</P
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><P
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>Simply typing <SPAN
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CLASS="emphasis"
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><I
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CLASS="EMPHASIS"
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>su</I
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></SPAN
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> will give you some root <A
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NAME="AEN6290"
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></A
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>privileges,<A
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NAME="AEN6292"
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></A
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> but there are minor <A
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NAME="AEN6294"
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></A
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>complications relating to environment <A
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NAME="AEN6296"
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></A
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>variables. It's generally considered better practice <A
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NAME="AEN6298"
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></A
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>to use <SPAN
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CLASS="emphasis"
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><I
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CLASS="EMPHASIS"
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>su - </I
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></SPAN
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>because it has no restrictions.<A
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NAME="AEN6301"
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></A
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></P
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><P
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></P
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></DD
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><DT
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>root</DT
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><DD
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><P
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>The superuser.<A
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NAME="AEN6308"
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></A
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> This user has power <A
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NAME="AEN6310"
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></A
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>over everything <A
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NAME="AEN6312"
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></A
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>and all, and can do anything with the system (including destroy <A
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NAME="AEN6314"
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></A
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>it, and of course fix <A
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NAME="AEN6316"
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></A
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>it :)). This user is used to perform most administration <A
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NAME="AEN6318"
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></A
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>functions <A
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NAME="AEN6320"
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></A
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>on the system.</P
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></DD
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></DL
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></DIV
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><DIV
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CLASS="SECT1"
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><H1
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CLASS="SECT1"
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><A
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NAME="USERS-AND-GROUPS"
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></A
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>Users/Groups</H1
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><P
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></P
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><P
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>All user information <A
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NAME="AEN6326"
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></A
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>is normally listed in the “/etc/passwd”<A
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NAME="AEN6328"
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></A
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> file and the group <A
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NAME="AEN6330"
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></A
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>information in the “/etc/groups”<A
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NAME="AEN6332"
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></A
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> file.</P
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><P
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>If you need to edit <A
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NAME="AEN6335"
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></A
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>either file it is recommended <A
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NAME="AEN6337"
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></A
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>that you use <SPAN
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CLASS="emphasis"
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><I
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CLASS="EMPHASIS"
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>vipw</I
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></SPAN
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> to edit the password file and <SPAN
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CLASS="emphasis"
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><I
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CLASS="EMPHASIS"
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>vigr</I
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></SPAN
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> to edit the group <A
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NAME="AEN6341"
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></A
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>file. These particular <A
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NAME="AEN6343"
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></A
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>commands take care of any processing <A
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NAME="AEN6345"
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></A
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>and locking <A
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NAME="AEN6347"
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></A
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>of the files before and after editing <A
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NAME="AEN6349"
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></A
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>them.</P
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><P
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>There is a lot of information about adding/removing/controlling users and groups,<A
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NAME="AEN6352"
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></A
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> this information is only the minimal <A
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NAME="AEN6354"
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></A
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>information required.</P
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><P
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></P
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><DIV
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CLASS="VARIABLELIST"
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><DL
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><DT
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>chsh</DT
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><DD
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><P
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><A
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NAME="AEN6361"
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></A
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>Used to change <A
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NAME="AEN6363"
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></A
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>your login <A
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NAME="AEN6365"
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></A
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>shell. </P
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><P
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>To list <A
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NAME="AEN6368"
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></A
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>the shells <A
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NAME="AEN6370"
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></A
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>available <A
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NAME="AEN6372"
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></A
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>type:</P
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><PRE
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CLASS="SCREEN"
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>chsh --list-shells</PRE
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><P
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>Simply type<SPAN
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CLASS="emphasis"
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><I
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CLASS="EMPHASIS"
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> chsh <A
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NAME="AEN6377"
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></A
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></I
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></SPAN
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>then [Enter], then type the name of the shell you would like to use every time <A
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NAME="AEN6379"
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></A
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>you login.<A
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NAME="AEN6381"
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></A
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></P
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></DD
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><DT
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>chfn</DT
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><DD
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><P
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><A
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NAME="AEN6387"
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></A
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>Change <A
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NAME="AEN6389"
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></A
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>finger <A
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NAME="AEN6391"
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></A
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>information. </P
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><P
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>The information <A
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NAME="AEN6394"
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></A
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>this command changes is reflected <A
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NAME="AEN6396"
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></A
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>in the /etc/passwd file, use this utility <A
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NAME="AEN6398"
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></A
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>to update <A
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NAME="AEN6400"
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></A
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>your real name, office <A
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NAME="AEN6402"
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></A
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>and home <A
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NAME="AEN6404"
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></A
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>phone numbers<A
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NAME="AEN6406"
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></A
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> (if they exist). </P
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><P
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>Use the <SPAN
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CLASS="emphasis"
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><I
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CLASS="EMPHASIS"
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>-f</I
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></SPAN
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> option to change a users full name. Use this tool as either <SPAN
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CLASS="emphasis"
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><I
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CLASS="EMPHASIS"
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>chfn</I
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></SPAN
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> or<SPAN
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CLASS="emphasis"
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><I
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CLASS="EMPHASIS"
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> chfn user_name </I
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></SPAN
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>(usable by root only).</P
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><P
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>Command syntax:</P
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><PRE
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CLASS="SCREEN"
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>chfn user_name</PRE
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></DD
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><DT
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>passwd</DT
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><DD
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><P
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><A
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NAME="AEN6418"
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></A
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>Changes the password of a user. You will need to be root if you want to change <A
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NAME="AEN6420"
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></A
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>other users passwords.<A
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NAME="AEN6422"
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></A
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></P
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><P
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>Simply type<SPAN
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CLASS="emphasis"
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><I
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CLASS="EMPHASIS"
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> passwd <A
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NAME="AEN6426"
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></A
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></I
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></SPAN
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>to change <A
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NAME="AEN6428"
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></A
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>your own password or to change <A
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NAME="AEN6430"
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></A
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>another users password <A
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NAME="AEN6432"
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></A
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>type:</P
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><PRE
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CLASS="SCREEN"
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>passwd username</PRE
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></DD
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></DL
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></DIV
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></DIV
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>Prev</A
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>Controlling services</TD
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> </TD
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