LX0-102 Practice

• /etc/profile (and files in /etc/profile.d)
• or
• ~/.bash_profile | ~/.bash_login | .profile
• p 23

• /etc/bashrc | /etc/bash.bashrc
• or
• ~/.bashrc
• p23

• function_name()
• {
• ls $1
• echo $2
• }
• Then can call cmd with args.
• Ex: function_name Myfile, STUPID
• p543

• /etc/skel
• Usually used for preference files.
• p.340

• PATH=$PATH:/sharefiles/NewDir:/othershare/OtherDir
• p44

• alias mynew1 "cmd -l; nextcmd -P"
• p50
• unalias to remove one.

• unset myvar
• p.57

• read VARNAME
• p.520

• declare -i MYVAR
• p522

• if condition then
•    cmds
• else
•    cmds
• fi
• p523

• if [ -d "$MYNEWPATH" ]; then
• Or use:
• if test -d $MYNEWPATH; then
• p523

• if [ -e "~/Myfile"]; then
• if test -e ~/Myfile; then
• p524

• if [ -f "$MYNEWPATH" ]; then
• or
• if test -f $MYNEWPATH; then

• For text,
• test "text1" = "text2"
• test "text1" != "text2"
• For numbers:
• test num1 -eq num2
• test num1 -lt num2
• test num2 -gt num2
• p525

• case $MYVAR in
•    val1 | val1a | val1b ) echo "Answer1"
•     ;;
•   val2 | val2a | val2b ) echo "Answer2"
•     ;;
•   * ) echo "Default answer."
•     ;;
• esac
• p526

• while condition
• do
•   script cmds
• done
• p527

• seq a b c
• If a only specified, seq increments by 1 until it reaches a.
• If a and b specified, seq starts from a, increments by 1 until it reaches b.
• If a, b, and c specified, seq starts from a, increments by b, until it reaches c.
• p 528

• for i in 'seq a b c"
•   do
•     cmds
•   done
• p 528

• It allows a cmd's stdout to be used as cmd line arguments for another cmd. Allow's nesting. Can be done with 
• cmd2 $(cmd1 -options)
• p543

• if [ -G /etc/myfile ]; then
• or
• if test -G /etc/myfile; then
• p524

• if [ -h /home/myfile ]; then
• if [ -L /home/myfile ]; then
• or
• if test -h /home/myfile; then
• if test -L /home/myfile; then
• p524

• if [ -O /etc/myfile ]; then
• if test -O /etc/myfile; then
• p525

• -r, or -w, or -x in the following:
• if [ -r /etc/myfile ]; then
• if test -x /etc/myfile]; then
• p525

• #!/bin/bash   or specify other cmd interpreter.
• Called hash-bang. She-bang, etc.
• p 518

• SUID: 4, SGID: 2, Sticky Bit: 1. Sticky on dirs means user can del files only for which they are owners. In chmod, it's 4th 1st #. E.g., instead of 777, it'd be 4777.
• p415

• SELECT
• p633

• UPDATE
• p633

• DELETE
• p633

• INSERT INTO
• p633

• CREATE TABLE
• p633

• ALTER TABLE
• p633

• DROP TABLE
• p633

• mysql -h localhost -u root -p
• -p means to prompt for a password.
• p635

• USE dbname
• p636

• SHOW TABLES
• p636

• CREATE TABLE mytable (variable1 VARCHAR(15), variable2 CHAR(12), vardatum DATE);
• p637

• DESCRIBE mytable
• p637

• INSERT INTO mytable VALUES ('Garbage',"Value","2011-08-29");
• p637

• SELECT field(s) FROM table [WHERE conditions] [ORDER BY field]
• Ex:
• SELECT first,phone FROM active; 
• View two fields only from all records.
• SELECT * FROM active
• View all records.
• p637

• DELETE FROM active WHERE last='Tracy';
• p637

• UPDATE table_name SET column=newvalue WHERE condition
• p638

SELECT custid,SUM(quantity)AS "Total" FROM active GROUP BY cust id;

• Cross-join is:
• SELECT field1 FROM table1,table2
• p638

• /etc/X11/xorg.conf (More modern, common)
• /etc/X11/XF86Config
• p.236

• Install fonts on server system to:
• /usr/share/X11/fonts or
• /usr/share/fonts
• Types of fonts (and dir's):
• bitmaps /100dpi and /75dpi
• Postscript Type 1 (scalable) /type1
• Truetype (scalable) /truetype
• On server enter: mkfontscale and mkfontdir to make index. Open port 7100. Server is "xfs start"
• Configure clients in /etc/X11/xorg.conf, under Section "Files", enter: FontPath "tcp/server_address:7100"
• p247

• Section "Files" Fonts & input device files
• Section "ServerFlags" Optional global flags
• Section "Module" For extensions & font rasterizers
• Section "InputDevice"
• Section "Modes" Defines video modes
• Section "Screen" Binds video board to monitor
•   Device "VMware SVGA" must exactly match id under device.
•   Subsection "Display"
• Section "Device" 1 section req'd per video adapter.
•   Identifier "VMware SVGA"
• Section "ServerLayout" Binds all others together.
• p239

• xhost +serveripaddress
• p724

• DISPLAY=X_client_Host_or_IP
• export DISPLAY
• p724

• xwininfo - displays window information
• xdpyinfo - displays server information
• p263

• X
• startx
• p245

• Generic config provided by X:
• Xorg -configure - autodetects all hw and makes /root/xorg.conf.new. To try, X -config /root/xorg.conf.new.
• Graphical utility is xorgcfg
• Some display conig utils:
• system-config-display
• system-config-keyboard
• system-config-mouse
• p243

• On most, loaded by init script. To start or stop, enter:
• /etc/init.d/xdm start | stop
• OR
• rcxdm start | stop
• Display mgr's are: xdm: gdm: kdm.
• To check which is started, chkconfig xdm -l
• To disable, chkconfig xdm off.
• p250

• For xdm, edit /etc/X11/xdm/Xresources.
• Modify xlogin* vars.
• p251

• In /etc/X11/xdm/Xservers file, locate line:
• :0 local /usr/bin/X -nolisten tcp -br vt7
• add: -bpp 16
• Where 16 is color depth, of 8, 16, or 24.
• p251

• On host: For xdm or kdm, edit /etc/X11/xdm/Xservers file. Find line:
• :0 local/usr/X11/R6/bin/X -nolisten tcp -br vt7
• Remove the -nolisten part. Save change, restart system.
• On host: For gdm, edit /etc/X11/gdm/gdm.conf and set DisallowTCP = to false.
• If on OpenSUSE, edit /etc/sysconfig/displayanger and set below two to yes:
• DISPLAY_REMOTE_ACCESS="yes"
• DISPLAY_XSERVER_TCP_PORT_6000_OPEN="ye"
• Open port 177 in xdm host's firewall (for xdm Control Protocol XDMCP).
• Open /etc/X11/xdm/Xaccess file (to config access control for XDMCP) on host. Add an entry for each client. Can also do *.mydomain.com. To restrict access, precede a line with a !. p252

• In AccessX,
• StickyKeys - Locks Ctrl & Shift keys.
• MouseKeys
• SlowKeys - Key must be held to send keystroke.
• ToggleKeys - Audible alert on num & capslock.
• RepeatKeys - Extra time before a key repeats.
• BounceKeys/Delay Keys - Slight delay b/w keystrokes.
• p254

brltty daemon must be loaded for Braille hardware. Orca is a good app for Braille. p261

Orca is a common one, as it can read from the Gnome desktop. Many others, like emacspeak, can only read from text based terminals. p257

• Orca popular (both screen magnifier and reader), Gnome Magnifier, and KDE Magnifier. Can start Orca from shell with orca -e magnifier.
• p257

GOK (Gnome Onscreen Keyboard) and GTkeyboard p254.

• useradd options username
• -D (no username) to view new user defaults
• -c Incl user's full name
• -e Date acct disable
• -f Days to disable acct after pw expiration.
• -g User's default grp
• -G Add'l groups
• -M Be created w/o home dir
• -m Specifies home dir.
• -p Specify user's encrypted pw. (openssl passwd -crypt)
• -r Specifies a system user
• -s Specify default shell
• -u Specify UID
• ex: useradd -c "Jackie McK" -m -p"q1GXA2Ox" -s "/bin/bash" jmacarthur
• p343

• /etc/default/useradd 
• Specifies Default group, home dir, shell, umask.
• /etc/login.defs
• Specifies UID & GID ranges, p/w min max ages, etc.
• /etc/skel
• p341

• passwd options username
• -S View acct status
• -l Lock (invalid pw)
• -u Unlock
• -d Removes pw
• -n Sets min days b/w pw changes.
• -x Sets max # days before pw change req'd.
• -w Sets # days warning.
• -i Sets # days after pw expiration before disabling acct.
• p344

• usermod options userid
• -c Edits user's full name
• -e Sets date of disablement
• -f Sets # days after pw expiration before acct disabled.
• -g Sets default grp
• -G Sets add'l grps
• -l Changes username
• -L Locks acct (disable pw)
• -m Sets home dir
• -p Sets user encrypted p/w. (openssl passwd -crypt)
• -s Default shell
• -u Sets UID
• -U Unlocks acct.
• p345

• userdel -r username
• -r says to remove the user's home directory.
• p346

• /etc/passwd
• username:password:UID;GID:Fullname:HomeDir:Defaultsh
• Ex:
• ksander:x:1001:100:Kimberly Sanders:/home/ksanders:/bin/bash
• p337

• /etc/shadow
• username:password:Last_Modified:Min_Days:Max_Days
• :Day_Warn:Disabled_Days:Expire
• Note: Last_Modified and Expire are days since 1/1/1970.
• Ex: ksanders:$@#$@#SSFDsdfsdf:15043:0:9999:7:::
• p338

• pwck 
• p339

• /etc/group
• Group:Password:GID:Users
• p348

/etc/gshadow p348

• groupadd options groupname
• -g Specify GID
• -p Specify password (openssl passwd -crypt)
• -r Specifies is a system group.
• p349

• groupmod options groupname
• -g Changes GID
• -p Changes pw (openssl passwd -crypt)
• -A adds user
• -R Removes user.
• Ex: groupmod -A "ktracy,m6soto"

• groupdel groupname
• p350

• chage option user
• -m Min days b/w pw changes
• -M Max days b/w pw changes
• -W Warning days before pw change req'd.
• p660

• /etc/init.d/atd
• To allow/deny access:
• /etc/at.allow
• /etc/at.deny
• To schedule job:
• at time
• Diff ways to schedule time.
• Type cmds. Output will be emailed to local acct.
• Ctrl+d
• To view queue, atq. To remove job. atrm job#.
• p500

• Fixed: HH:MM (am or pm is OK), Noon, Midnight, Teatime (1600), MMDDYY, MM/DD/YY, MM.DD.YY, HH:MM MMDDYY.
• Relative: now, now +  value (5 minutes, 2 hours, 3 days), 2 pm today, 2pm tomorrow.
• p500

• /etc/init.d/cron
• Config'd in /etc/crontab
• Scripts run from:
• /etc/cron.hourly
• /etc/cron.daily
• /etc/cron.weekly
• /etc/cron.monthly
• /etc/cron.d
• To config /etc/cron.d intervals, 
• Create /etc/cron.d/crontab
• Min  Hrs  DayofMo Mnth  DaysofWk Cmd
• 5  23 * * 1-6  /bin/tar -cvf /media/backup.tar /home
• Backups up at 23:05 every day of every mo on Mon-Sat.
• p502

• /etc/cron.allow and /etc/cron.deny. By default, only cron.deny is created that blocks guest acct. All others can create crontab scheds. When a cron.allow is created, *only* users listed can make scheds. All others denied. User crontabs stored in /var/spool/cron/
• p504

• crontab options
• -e Edit, or make new. Opens vi.
• -l To list crontab
• -r To remove crontab.
• Uses same format:
• Min  Hr  DayofMo Month DaysofWk Cmd
• p504

• LC_CTYPE Default char type & encoding
• LC_MESSAGES Config's natural lang msgs
• LC_COLLATE Sorting rules
• LC_NUMERIC # format
• LC_MONETARY Currency format
• LC_TIME Date and time display
• LC_PAPER Default paper size
• LC_NAME Default personal name fmt
• LC_ADDRESS Default address fmt
• LC_TELEPHONE Default phone # fmts
• LC_MEASUREMENT Default meas. units
• LC_ALL Overrides all other LC Env Vars
• LANG Specifies default locale val for all LC-vars
• LANGUAGE Overrides LC_Messages
• p163

• language_territory.codset @modifier.
• Ex:
• en_US.UTF-8
• UTF-8 is known as Unicode.
• p164

• If LC_ALL is defined, it's used. No other LCs used.
• If LC_ALL is undefined, specific LC vars are checked.
• If LC var has null val, then LANG var is used.
• p165.

• /usr/bin/locale
• p165

• hwclock
• -r or --show (Is default option w/o cmd line options)
• --set --date="9/16/11 08:00:00" (Arg is local time, even if hw clock is set to UTC)
• -s or --hctosys Sets sys time to hwclock time.
• -w or --systohc Sets hwclock time to sys time.
• --utc or --localtime Specifies hwclock is config'd to use either UTC or local time.
• p167/617

• In /etc/sysconfig/clock, change as follows:
• HWCLOCK="-u"   #for UTC
• HWCLOCK="--localtime" #for local time.
• p107.3

• On some (e.g. Ubuntu), it's /etc/timezone
• America/Denver
• On some (e.g. OpenSUSE), it's /etc/sysconfig/clock
• TIMEZONE="America/Boise"
• Can check it by using date cmd.
• Available timezones in /usr/share/zoneinfo.
• p168

• Debian based (Ubuntu) use tzconfig. Others (OpenSUSE/Fedora) use tzselect.
• p168.

• ln -sf /usr/share/zoneinfo/MST /etc/localtime
• Note that -f is "force", which removes an already existing destination file.
• p169

• iconv -f source_encoding -t dest_encoding -o outputfile inputfile
• p166

• iso8859 (aka latin-9) - designed for Western European languages
• ASCII - English based char encoding
• UTF-8 Unicode - for all languages, worldwide.
• p169.

• date mmddhhmmyyyy
• Had to search net.

• Ensure pkg installed. Then check /etc/nftp.conf file. Ensure following lines exist, as fallback:
• server 127.127.1.0 # local clock (LCL)
• fudge 127.127.1.0 stratum 10 # LCL is unsynchronized
• Then ensure not on insane time (>17 min diff). If it is, run "ntpdate addrOfTimeProv" to do initial sync (ntpd must be stopped!). Newer ntp versions let you specify "etc/init.d/ntp ntptimeset" which does quick sync. Then start daemon. Do "insserv ntp" to have it run on start.
• p621

• ntpq -p  - Shows status of daemon.
• ntptrace - Traces how consumer is receiving time from provider (incl stratum, etc).
• p623

• pool.ntp.org
• Roundrobin volunteer servers
• p622

• Logs stored in /var/log. Most svcs config'd to write to /dev/log, which is run by syslogd svc. syslog then looks at /etc/syslog.conf file to determine what to do. Syntax for etc/syslog.conf is:
• facility.priority    file
• Facilities are subsystems that provide msgs. All assigned to one: authpriv, cron, daemon, kern (kernel), lpr, mail, news, syslog (for daemon itself), user, uucp, local0-local7 (for self-dev'd applications). Priorities are usually handled by klogd. Priority choices: debug (All info), info, notice, warn, err (Serious), crit alert or emerg (critical). p680

• /var/log/
• boot.log - Log entries from daemons during startup.
• boot.msg - Shows all msgs displayed on screen during boot.
• faillog - Failed auth attempts
• firewall - Firewall log entries
• lastlog - Last login info for users. View w lastlog cmd.
• mail - Msgs from postfix or sendmail.
• messages - Messages from most running processes. One of most useful.
• warn - Warning messages.
• wtmp - List of user's authenticated. View w last cmd.
• xinetd.log - 
• p680

logrotate. Config'd with /etc/logrotate.conf. Contains defaults. Can customize for certain ones with placing config file in /etc/logrotate.d. p682

• logger -p facilility.priority "log_message"
• p684

• Edit /etc/aliases. Add using this format:
• alias: list of actual email addys (separated by commas).
• Then run newaliases cmd to enable them. p631.

Create ~/.forward file that contains email addys, delimited by commas. Note that msgs will not be delivered to actual address. p630

• sendmail - oldest. Non-componentized. Can be hard to config.
• postfix - Popular. Modular.
• qmail - Modular. Componentized. Untrusting components. Proprietary licensing. 
•   2 components:
•   QMQP (Quick Mail Queing Protocol) - Allows sharing of queues among diff MTAs.
•   QMTP (Quick Mail Transport Protocol - Like SMTP but faster.
• exim - Nonmodular. Single executable, but easy to config.
• p628.

• mail [recipient]
• Cmds in mail
• t - type msg
• d - del msg
• u - undelete msg
• n - next msg
• e - edit msg
• R - reply msg
• r - reply all
• m - mail new
• q - quit
• mailq - View unread msgs in mailq.
• p631

• cupd. Supports printing over IPP on port 631.
• Parts:
• scheduler - Webserver running on port 631.
• filters - Located in /usr/lib/cups/filter. PDLs (page desc langs)
• backends - provide interface from scheduler to hardware. Located in /usr/lib/cups/backend.
• p603

• Config files located in /etc/cups. Main config is /etc/cups/cupsd.conf
• To add an admin user, "lppasswd -g sys -a root". Accts contained in /etc/cups/passwd.md5.
• Printers defined in /etc/cups/printers.conf. To add click Administration | Printers | Add Printer | etc...
• p609

• lp -d printername filename
• Options:
• -n x    - Prints x copies
• -m      - Emails conf email to my acct when done
• -q       - Sets priority of print job
• -o landscape   - Prints landscape mode
• -o sides=2       - Prints doublesided.
• p610

• lpstat -t. Shows default printer, current print job, and pending.
• p611

cancel [jobname]. p612

lpoptions -d printername. Sets for everyone. Individual users can set default by creating ~/.lpoptions and stating "default printername."

• lpoptions -l
• p612

• lpd (line printer daemon)
• lpr -P printer-name filename   To print
• lpc status     For printer status
• lpq             View pending jobs
• lprm   jobnum        Cancel pending job.
• p613

• /etc/resolv.conf
• search mydomain.com      -  Used to fill incomplete hostnames.
• nameserver 192.168.1.1   - Actually nameserver
• p580

• /etc/sysconfig/network/routes
• Line in here is:
• default 192.168.1.1 - -
• p566

• 20 FTP
• 21 FTP
• 22 SSH
• 23 Telnet
• 25 SMTP
• 53 DNS
• 80 HTTP
• 119 NNTP
• 139 NetBIOS Session Svc
• 143 IMAP
• 161 SNMP
• 443 HTTPS
• 465 URL Rendezvous for SSM (Cisco)
• 993 IMAP over SSL
• 995 POP3 over TLS/SSL
• Source: Inet

• Manual:
• ifconfig eth0 192.168.1.1 netmask 255.255.255.0 broadcast 192.168.1.255
• Auto:
• dhclient eth0
• One time use only
• p572

• Create/Edit /etc/sysconfig/network/ifcfg-eth0 or /ifcfg-eth-id-00:0c:29:d1:52:d4, on some distribs.
• BOOTPROTO="static" or "dhcp"
• STARTMODE="auto"  or manual or onboot. Start @ boot?
• IPADDR="192.168.1.81/24"
• NETMASK="255.255.255.0" Another option, than /24.
• NETWORK="192.168.1.0" Defines net segment
• BROADCAST="192.168.1.255" 
• LABEL_0='0'    These 3 lines define IPv6 addr
• IP_ADDR0='2607:f0d0:1002:0011:0000:0000:0000:0003'
• PREFIXLEN_0='64'
• p573

• route add -net 192.168.5.0 netmask 255.255.255.0 gw 192.168.1.254
• To remove, same options, but start with
• route del 
• To add default,
• route add default gw 192.168.1.254
• p578