File:  [NetBSD Developer Wiki] / wikisrc / Attic / the_netbsd_system_manager__39__s_manual.mdwn
Revision 1.3: download - view: text, annotated - select for diffs
Fri Jun 22 21:14:08 2018 UTC (2 years, 4 months ago) by maya
Branches: MAIN
CVS tags: HEAD
Refer to dhcpcd.

No idea why would want to view its lease files, they don't appear to be
human-readable.

    1: This is the NetBSD System Manager's Manual, derived from the [bsdwiki book](http://bsdwiki.reedmedia.net/). 
    2: 
    3: **Contents**
    4: 
    5: [[!toc levels=3]]
    6: 
    7: #  Installing and Upgrading NetBSD 
    8: 
    9: ##  Recognize the installation program used by NetBSD 
   10: 
   11: ##  Recognize which commands are available for upgrading 
   12: 
   13: ##  Understand the difference between a pre-compiled binary and compiling from source 
   14: 
   15: ##  Understand when it is preferable to install a pre-compiled binary and how to do so 
   16: 
   17: if cpu power is low and or disk space is limited. 
   18: 
   19: ##  Recognize the available methods for compiling a customized binary 
   20: 
   21: ##  Determine what software is installed on a system 
   22: 
   23: To obtain a list of all third-party software installed on a NetBSD system using the [pkgsrc](http://www.pkgsrc.org) package management system, execute the [pkg_info(1)](http://netbsd.gw.com/cgi-bin/man-cgi?pkg_info++NetBSD-current) command with no arguments. 
   24: 
   25: $ pkg_info
   26:     
   27: 
   28: ##  Determine which software requires upgrading 
   29: 
   30: To determine which software requires upgrading, you have to install pkg_chk first, which is available in [pkgtools/pkg_chk](http://pkgsrc.se/pkgtools/pkg_chk) from pkgsrc. When done, asure that your pkgsrc tree is up to date and enter: 
   31: 
   32:     # pkg_chk -q -u
   33:     
   34: 
   35: to see which packages needs to be upgraded. 
   36: 
   37: ##  Upgrade installed software 
   38: 
   39: There are many ways to upgrade installed software use one of the following 
   40: 
   41:   * pkgtools/[pkg_rolling-replace](http://pkgsrc.se/pkgtools/pkg_rolling-replace)
   42:   * pkgtools/[pkg_chk](http://pkgsrc.se/pkgtools/pkg_chk)
   43: 
   44: or use `make update` in the pkgsrc directory of the package that needs to be updated. 
   45: 
   46: ##  Determine which software have outstanding security advisories 
   47: 
   48: You can use pkgsrc's auditing feature to (periodicaly) check for package vulnerabilites. 
   49: 
   50: Install [security/audit-packages](http://pkgsrc.se/security/audit-packages) first. 
   51: 
   52: _If you dont know how to install a package, read the section about installing packages, or the [pkgsrc user guide](http://www.netbsd.org/docs/pkgsrc/).
   53: 
   54: To audit the packages, you have to download the vulnerability list: 
   55:     
   56:     # download-vulenability-list
   57:     
   58: 
   59: You can put the following to your crontab to automate this: 
   60:     
   61:     0 3 * * * /usr/pkg/sbin/download-vulnerability-list >/dev/null 2>&1
   62:     
   63: 
   64: This will update the vulnerability list every day at 3AM. You may wish to do this more often than once a day. 
   65: 
   66: You can also ask NetBSD to include the vulnerability check in the security report: 
   67: 
   68: Put this into `/etc/security.local`: 
   69:     
   70:     if [ -x /usr/pkg/sbin/audit-packages ]; then
   71:             /usr/pkg/sbin/audit-packages
   72:     fi
   73:     
   74: 
   75: ##  Follow the instructions in a security advisory to apply a security patch 
   76: 
   77: #  Securing the NetBSD Operating System 
   78: 
   79: ##  Determine the system's security level 
   80: 
   81: See the value of `kern.securelevel` (cf. [sysctl(8)](http://netbsd.gw.com/cgi-bin/man-cgi?sysctl+8+NetBSD-current)) : 
   82: 
   83: $ sysctl kern.securelevel
   84:     kern.securelevel = 1
   85:     
   86: 
   87: ##  Recognize basic recommended access methods 
   88: 
   89: ##  Configure an SSH server according to a set of requirements 
   90: 
   91: Edit `/etc/ssh/sshd_config`. When all seems fine, relaunch [sshd(8)](http://netbsd.gw.com/cgi-bin/man-cgi?sshd++NetBSD-current) daemon with : 
   92: 
   93:     # /etc/rc.d/sshd restart
   94:     
   95: 
   96: If you are working remotely via an SSH connexion, don't worry: with privileges separation (as default), your working connexion won't be claused. 
   97: 
   98: ##  Configure an SSH server to use a key pair for authentication 
   99: 
  100: In `/etc/ssh/sshd_config`, uncomment lines: 
  101:     
  102:     PasswordAuthentication no
  103:     PermitEmptyPasswords no
  104:     
  105: 
  106: If you want to connect as root (don't do this), at least use keys with: 
  107:     
  108:     PermitRootLogin without-password
  109:     
  110: 
  111: Don't forget to relaunch daemon. 
  112: 
  113: ##  Preserve existing SSH host keys during a system upgrade 
  114: 
  115: The SSH keys live under `/etc/ssh`. Just [tar(1)](http://netbsd.gw.com/cgi-bin/man-cgi?atr++NetBSD-current) up all key files and extract the archive on the new system. 
  116: 
  117: ##  Recognize alternate authentication mechanisms 
  118: 
  119: ##  Recognize alternate authorization schemes 
  120: 
  121: ##  Recognize firewalls and rulesets 
  122: 
  123: To see input rules: 
  124:     
  125:     # ipfstat -hin
  126:     
  127: 
  128: `-o` (instead of `-i`) option gives output rules. `-6` option manipulates IPv6 rules. `-n` display groups and rules numbers, useful when searching from logs. 
  129: 
  130: IPNAT rules can be listed with: 
  131:     
  132:     # ipnat -l
  133:     
  134: 
  135: ##  Recognize utilities that shape traffic or control bandwidth 
  136: 
  137: ##  Recognize mechanisms for encrypting devices 
  138:     
  139:     $ man cgd
  140:     
  141: 
  142: ##  Recognize methods for verifying the validity of binaries 
  143: 
  144: By default, `/etc/daily` launch `/etc/security` which uses [mtree(8)](http://netbsd.gw.com/cgi-bin/man-cgi?mtree++NetBSD-current). 
  145: 
  146: 
  147: To check if [veriexec(4)](http://netbsd.gw.com/cgi-bin/man-cgi?veriexec++NetBSD-current) is up: 
  148:     
  149: 
  150: $ sysctl kern.veriexec.strict
  151:     kern.veriexec.strict=1
  152:     
  153: 
  154: Read [veriexec chapter](http://www.netbsd.org/docs/guide/en/chap-veriexec.html) from [NetBSD Guide](http://www.netbsd.org/docs/guide/en/) for more information. 
  155: 
  156: ##  Enable exploit mitigation 
  157: 
  158: Follow advices in [security(8)](http://netbsd.gw.com/cgi-bin/man-cgi?security++NetBSD-current) man page. 
  159: 
  160: 
  161: ##  Recognize methods for restraining a service 
  162: 
  163:   * [chroot(8)](http://netbsd.gw.com/cgi-bin/man-cgi?chroot+8+NetBSD-current)
  164:   * [systrace(1)](http://netbsd.gw.com/cgi-bin/man-cgi?systrace+1+NetBSD-current)
  165:   * [Xen](http://www.netbsd.org/ports/xen)
  166: 
  167: ##  Modify the system banner 
  168: 
  169: Edit `/etc/motd`. 
  170: 
  171: You can also add a banner before SSH connexion; to do that, add: 
  172:     
  173:     Banner /etc/ssh/issue
  174:     
  175: 
  176: in `/etc/ssh/sshd_config` and put what you want to be displayed before SSH auth in file `/etc/ssh/issue`. 
  177: 
  178: #  Files, Filesystems and Disks 
  179: 
  180: ##  Mount or unmount local filesystems 
  181: 
  182: To mount a file system, use the [mount(8)](http://netbsd.gw.com/cgi-bin/man-cgi?mount++NetBSD-current) command. The general syntax is: 
  183:     
  184: 
  185:     # mount [options] device_node mount_point
  186:     
  187: 
  188: The available options may be found in the man page. Typically, it will be necessary to at least use the `-t` command to specify the type of filesystem to be mounted. For example, to mount a CD-ROM device, specify the ISO 9660 format with a command like the following: 
  189:     
  190:     # mount -t cd9660 /dev/cd0d /mnt/cdrom
  191:     
  192: 
  193: To unmount a mounted filesystem, use the [umount(8)](http://netbsd.gw.com/cgi-bin/man-cgi?umount++NetBSD-current) command. To unmount the mounted filesystem `/mnt/cdrom`, simply execute: 
  194:     
  195:     # umount /mnt/cdrom
  196:     
  197: 
  198: Note that unmounting a filesystem will fail if any running process has a directory in that filesystem as its present working directory. For example: 
  199:     
  200:     # mount -t cd9660 /dev/cd0d /mnt/cdrom
  201:     # cd /mnt/cdrom
  202:     # umount /mnt/cdrom
  203:     umount: /mnt/cdrom: Device busy
  204:     # cd
  205:     # umount /mnt/cdrom
  206:     #
  207:     
  208: 
  209: ##  Configure data to be available through NFS 
  210: 
  211: Let's share `/export/data`. Create the file `/etc/exports` as: 
  212:     
  213:     $ cat /etc/exports
  214:     /export/data -maproot=nobody -ro -network 192.168.1.0 -mask 255.255.255.0
  215:     
  216: 
  217: Here, the file system will be read only (option `-ro`), available only for clients from `192.168.1.0/24` and root access from clients will be mapped as `nobody` access on server (we don't have confidence with our clients). The syntax and options are documented in [exports(5)](http://netbsd.gw.com/cgi-bin/man-cgi?exports+5+NetBSD-current). 
  218: 
  219: We have to start [rpcbind(8)](http://netbsd.gw.com/cgi-bin/man-cgi?rpcbind+8+NetBSD-current), [mountd(8)](http://netbsd.gw.com/cgi-bin/man-cgi?mountd+8+NetBSD-current), [rpc.lockd(8)](http://netbsd.gw.com/cgi-bin/man-cgi?rpc.lockd+8+NetBSD-current), [nfsd(8)](http://netbsd.gw.com/cgi-bin/man-cgi?nfsd+8+NetBSD-current) and [rpc.statd(8)](http://netbsd.gw.com/cgi-bin/man-cgi?rpc.statd+8+NetBSD-current). In order to do that, edit `/etc/rc.conf` and set: 
  220:     
  221: rpcbind=YES   rpcbind_flags="-l"
  222:     mountd=YES
  223:     nfs_server=YES
  224:     statd=YES
  225:     lockd=YES
  226:     
  227: 
  228: The flag `-l` tells [rpcbind(8)](http://netbsd.gw.com/cgi-bin/man-cgi?rpcbind+8+NetBSD-current) to use _libwrap_ ([hosts_options(5)](http://netbsd.gw.com/cgi-bin/man-cgi?hosts_options+5+NetBSD-current)). Edit the `/etc/hosts.access` and set: 
  229:     
  230: rpcbind: 192.168.1.0/255.255.255.0 ALLOW
  231:     
  232: 
  233: to allow clients to connect to the server. 
  234: 
  235: On the clients, we have to start [rpcbind(8)](http://netbsd.gw.com/cgi-bin/man-cgi?rpcbind+8+NetBSD-current), [rpc.statd(8)](http://netbsd.gw.com/cgi-bin/man-cgi?rpc.statd+8+NetBSD-current) and [rpc.lockd(8)](http://netbsd.gw.com/cgi-bin/man-cgi?rpc.lockd+8+NetBSD-current); edit `/etc/rc.conf` and set: 
  236:     
  237: rpcbind=YES   rpcbind_flags="-l"
  238:     nfs_client=YES
  239:     statd=YES
  240:     lockd=YES
  241:     
  242: 
  243: Now, lets mount the file system on the client: 
  244:     
  245:     # mount -o ro server:/export/data /data
  246:     $ mount | grep data
  247:     server:/export/data on /data type nfs (read-only)
  248:     
  249: 
  250: Don't forget to add a line in `/etc/fstab` ([fstab(5)](http://netbsd.gw.com/cgi-bin/man-cgi?fstab+5+NetBSD-current)): 
  251:     
  252: 
  253: server:/export/data /data nfs ro 0 0
  254:     
  255: 
  256: to mount the file system at boot time. That's all. 
  257: 
  258: See the NetBSD Guide [[1]](http://www.netbsd.org/docs/guide/en/chap-net-misc.html#chap-net-misc-nfs) for more details. 
  259: 
  260: ##  Determine which filesystems are currently mounted and which will be mounted at system boot 
  261: 
  262: A list of currently mounted filesystems can be obtained by running the [mount(8)](http://netbsd.gw.com/cgi-bin/man-cgi?mount++NetBSD-current) command without any arguments. 
  263: 
  264: The file [fstab(5)](http://netbsd.gw.com/cgi-bin/man-cgi?fstab++NetBSD-current) in `/etc` contains information about which files are mounted at system boot and what options they are mounted with, whether they should be [fsck(8)](http://netbsd.gw.com/cgi-bin/man-cgi?fsck++NetBSD-current)ed and if so in what order, etc. 
  265: 
  266: ##  Determine disk capacity and which files are consuming the most disk space 
  267: 
  268: Disk capacity: 
  269:     
  270:     $ df -h
  271:     
  272: 
  273: Find the size of files in a directory: 
  274:     
  275:     $ du -sk
  276:     
  277: 
  278: Report by file size: 
  279:     
  280:     $ du -k | sort -n
  281:     
  282: 
  283: ##  Create and view symbolic or hard links 
  284: 
  285: Symbolic link: 
  286:     
  287:     $ ln -s sourcefile targetfile
  288:     
  289: 
  290: Hard link: 
  291:     
  292:     $ ln sourcefile targetfile
  293:     
  294: 
  295: ##  View file permissions and modify them using either symbolic or octal mode 
  296: 
  297: View file permissions: 
  298:     
  299:     $ ls -l filename
  300:     
  301: 
  302: Change file permissions 
  303:     
  304:     $ chmod 644 filename
  305:     
  306: 
  307: ##  Modify a file's owner or group 
  308: 
  309: The [chown(8)](http://netbsd.gw.com/cgi-bin/man-cgi?chown++NetBSD-current) command can be used to modify a file's owner or group. 
  310: 
  311: 
  312: To change the owner of the file `somefile` to the user `someuser`, execute: 
  313:     
  314:     chown someuser somefile
  315:     
  316: 
  317: Similarly, to change the group of the file `somefile` to the group `somegroup`, execute: 
  318:     
  319:     chown :somegroup somefile
  320:     
  321: 
  322: If you like, can change both the group and owner of a file with a single command. To implement both of the modifications made by the two commands above, execute: 
  323:     
  324:     chown someuser:somegroup somefile
  325:     
  326: 
  327: Note that there is also a [chgrp(1)](http://netbsd.gw.com/cgi-bin/man-cgi?chgrp++NetBSD-current) command to change the group of a file. 
  328: 
  329: 
  330: To change the group of the file `somefile` to the group `somegroup`, execute: 
  331:     
  332:     chgrp somegroup somefile
  333:     
  334: 
  335: ##  Backup and restore a specified set of files and directories to local disk or tape 
  336: 
  337: Create your (compressed) archive with: 
  338:     
  339:     $ tar cvfz backup.tgz somedirectory/
  340:     
  341: 
  342:   * `c` option: create the archive, 
  343:   * `z` option: compress the archive whith [gzip(1)](http://netbsd.gw.com/cgi-bin/man-cgi?gzip++NetBSD-current), 
  344:   * `f` option: output to a file; if you miss this option, [tar(1)](http://netbsd.gw.com/cgi-bin/man-cgi?tar++NetBSD-current) will output archive to `/dev/st0` (default tape), 
  345:   * `v` option: verbose output ie. files added to archive will be displayed. 
  346: 
  347: To restore, use: 
  348:     
  349:     $ tar xzpf backup.tgz
  350:     
  351: 
  352:   * `x` option: extract the archive, 
  353:   * `p` option: preserve ownership. 
  354: 
  355: See also [pax(1)](http://netbsd.gw.com/cgi-bin/man-cgi?pax++NetBSD-current) and [cpio(1)](http://netbsd.gw.com/cgi-bin/man-cgi?cpio++NetBSD-current). 
  356: 
  357: ##  Backup and restore a file system 
  358:     
  359:     # dump 0f - | (cd /altroot; retore rf -)
  360:     
  361: 
  362: See [dump(8)](http://netbsd.gw.com/cgi-bin/man-cgi?dump++NetBSD-current) and [restore(8)](http://netbsd.gw.com/cgi-bin/man-cgi?restore++NetBSD-current). 
  363: 
  364: 
  365: ##  Backup using ffs snapshots 
  366: 
  367: Snapshots allows to work with an atomic file system copy taken at a the time of the snapshot. This is very useful to for instance backup a file system on which there may be running database applications such as PostgreSQL, without the need to stop and restart the database application. 
  368: 
  369: See [fssconfig(8)](http://netbsd.gw.com/cgi-bin/man-cgi?fssconfig++NetBSD-current) and [fss(4)](http://netbsd.gw.com/cgi-bin/man-cfi?fss++NetBSD-current) for more details. Here for the sake of an example we will suppose that we want to backup a live `/` file system using `rsync` to a `/backup` file system. 
  370: 
  371: 
  372: Let's first create the "atomic" snapshot of the `/` file system: 
  373:     
  374:     # fssconfig -cx fss0 / /tmp/back
  375:     
  376: 
  377: We now have configured the device `/dev/fss0` to be a snapshot mirror of the `/` file system, using a temporary log of `/tmp/back` to which new writes will be added for as long as the snapshot device is configured. This file will be automatically deleted at device unconfiguration because of the optional `-x` switch. You may now use that device with the `dump` command or mount it and use other backup commands such as `pax`, `tar` or `rsync` as you wish. 
  378:     
  379:     # mount -o ro /dev/fss0 /mnt
  380:     
  381: 
  382: We have now mounted the atomic copy of the file system to `/mnt`. Let's update our `/backup` file system from it: 
  383:     
  384:     # rsync -vaHx --delete /mnt/ /backup/
  385:     
  386: 
  387: So our "atomic" live backup is done and we now no longer need our snapshot: 
  388:     
  389:     # umount /mnt
  390:     # fssconfig -u fss0
  391:     
  392: 
  393: ##  Determine the directory structure of a system 
  394: 
  395: ##  Manually run the file system checker and repair tool 
  396: 
  397: For FFS filesystems (example, in this case is the first slice on your first IDE hard disk): 
  398:     
  399:     # fsck /dev/rwd0a
  400:     
  401: 
  402: The `-y` option should be added with caution: [fsck(8)](http://netbsd.gw.com/cgi-bin/man-cgi?fsck+8+NetBSD-current) assumes yes as the default answer for all its questions. Use it at your own risks. 
  403: 
  404: 
  405: ##  View and modify file flags 
  406: 
  407: use chflags to modify file flags, for example: 
  408:     
  409:     $ chflag uchange pkgsrc.tar.gz
  410:     $ ls -lo pkgsrc.tar.gz
  411:     -rw-r--r--  1 zafer  users  uchg 32072480 May 19 09:12 pkgsrc.tar.gz
  412:     
  413: 
  414: ##  Monitor the virtual memory system 
  415: 
  416: #  Users and Accounts Management 
  417: 
  418: ##  Protect authentication data 
  419: 
  420: ##  Create, modify and remove user accounts 
  421: 
  422: create 
  423:     
  424:     # useradd -m johndoe 
  425:     
  426: 
  427: delete 
  428:     
  429:     # userdel johndoe
  430:     
  431: 
  432: modify 
  433:     
  434:     # usermod -m -d /home/foo johndoe
  435:     
  436: 
  437: ##  Create a system account 
  438: 
  439: ##  Control which files are copied to a new user's home directory during account creation 
  440: 
  441: The _-k_ option of the [useradd(8)](http://netbsd.gw.com/cgi-bin/man-cgi?useradd++NetBSD-current) command can be used to specify a "skeleton directory". The contents of the specified skeleton directory will be copied to the new user's home directory. If no skeleton directory is specified with _-k_, the default of `/usr/skel/` is used. 
  442: 
  443: 
  444: ##  Change a password 
  445: 
  446: The [passwd(1)](http://netbsd.gw.com/cgi-bin/man-cgi?passwd++NetBSD-current) command can be used to change a password. 
  447: 
  448: 
  449: Executing passwd with no arguments will change the password of the executing user. The existing password must be supplied before changes can be made. The new password must be entered identically twice, to ensure the password is not set to a misspelling of the intended password. The process looks something like this - note that passwords do not echo: 
  450:     
  451:     $ passwd
  452:     Changing local password for user.
  453:     Old password:
  454:     New password:
  455:     Retype new password:
  456:     
  457: 
  458: The superuser may change the password of an arbitrary user by supplying that user's name as the only argument to passwd. Root does not need to supply the user's existing password, and may simply supply a new one. The process looks something like this: 
  459:     
  460:     # passwd user
  461:     Changing local password for user.
  462:     New password:
  463:     Retype new password
  464:     
  465: 
  466: ##  Force the user to change their password upon next login 
  467:     
  468:     # usermod -F johndoe
  469:     
  470: 
  471: ##  Change the encryption algorithm used to encrypt the password database 
  472: 
  473: The encryption algorithm or algorithms used to encrypt the password database are specified in the [passwd.conf(5)](http://netbsd.gw.com/cgi-bin/man-cgi?passwd.conf++NetBSD-current) file in `/etc`. 
  474: 
  475: 
  476: The syntax of the file is straightforward and is made clear by the following example, taken from the man page: 
  477: 
  478: _Use MD5 as the local cipher and old-style DES as the YP cipher. Use blowfish with 2^5 rounds for root:_
  479:     
  480:           default:
  481:                localcipher = md5
  482:                ypcipher = old
  483:     
  484:     
  485:           root:
  486:                localcipher = blowfish,5
  487:     
  488: 
  489: The algorithm choices are: `old', `newsalt,<rounds>', `md5', `sha1,<rounds>', and `blowfish,<rounds>'. Consult the man page for details on allowable round parameters. 
  490: 
  491: ##  Change a user's default shell 
  492: 
  493: Make your market in `/etc/shells` file and pick up one. For example, we want to change the shell of _johndoe_ to `/bin/ksh`: 
  494:     
  495:     # chsh -s /bin/ksh johndoe
  496:     
  497: 
  498: or 
  499:     
  500:     # chpass -s /bin/ksh johndoe
  501:     
  502: 
  503: See [chsh(1)](http://netbsd.gw.com/cgi-bin/man-cgi?chsh+1+NetBSD-current) for mor details. 
  504: 
  505: 
  506: ##  Lock a user account or reset a locked user account 
  507: 
  508: Lock 
  509:     
  510:     # usermod -C yes johndoe
  511:     
  512: 
  513: Unlock 
  514:     
  515:     # usermod -C no johndoe
  516:     
  517: 
  518: ##  Determine identity and group membership 
  519:     
  520:     $ id
  521:     
  522: 
  523: ##  Determine who is currently on the system or the last time a user was on the system 
  524: 
  525: Enter 
  526:     
  527:     $ w
  528:     
  529: 
  530: to determine who is currently on the system. 
  531: 
  532: Enter 
  533:     
  534:     $ last
  535:     
  536: 
  537: to determine the last time a user was on the system. 
  538: 
  539: ##  Enable accounting and view system usage statistics 
  540: 
  541: #  Basic System Administration 
  542: 
  543: ##  Determine which process are consuming the most CPU 
  544: 
  545: The [top(1)](http://netbsd.gw.com/cgi-bin/man-cgi?top++NetBSD-current) command displays and regularly updates a list of top CPU consuming processes. The list includes details such as the command used to create the process, the user who ran that command, the process' PID, what state the process is currently in and how much memory and CPU time the process is consuming. 
  546: 
  547: 
  548: ##  View and send signals to active processes 
  549: 
  550: The [ps(1)](http://netbsd.gw.com/cgi-bin/man-cgi?ps++NetBSD-current) command can be used to view a list of names and details (such as PID) currently active processes. Exactly which processes and what details about them are displayed can be customised using the options described in the man page. To get the default details of _all_ processes, execute: 
  551: 
  552: 
  553:     $ ps ax
  554:     
  555: 
  556: Sending signals to processes is done using the [kill(1)](http://netbsd.gw.com/cgi-bin/man-cgi?kill++NetBSD-current) command. The signal to be sent may be specified either by name (e.g. HUP, INT, QUIT, ABRT, KILL, ALRM, TERM; see also `kill -l` output) or by an integer code, as specified in the man page. 
  557: 
  558: 
  559: The simplest syntax for [kill(1)](http://netbsd.gw.com/cgi-bin/man-cgi?kill++NetBSD-current) is: 
  560: 
  561: 
  562: $ kill {signal name or code} pid
  563:     
  564: 
  565: where `pid` is the PID of the process to be killed. Note that if no signal name or code is specified (i.e. just `kill pid` is used) then a TERM signal is sent by default. 
  566: 
  567: Note that it is not typical to immediately know the PID of a process one wants to signal. One can either use the [ps(1)](http://netbsd.gw.com/cgi-bin/man-cgi?ps++NetBSD-current) command as described above to find the pid (perhaps with the assistance of [grep(1)](http://netbsd.gw.com/cgi-bin/man-cgi?grep++NetBSD-current), or one can use the [pkill(1)](http://netbsd.gw.com/cgi-bin/man-cgi?pkill++NetBSD-current) command, which works like [kill(1)](http://netbsd.gw.com/cgi-bin/man-cgi?kill++NetBSD-current) except that it accepts a process name rather than a PID. 
  568: 
  569: ##  Use an rc(8) script to determine if a service is running and start, restart or stop it as required 
  570: 
  571: To see if a service is running, execute that service's [rc(8)](http://netbsd.gw.com/cgi-bin/man-cgi?rc++NetBSD-current) script with an argument of `status`. The output will indicate if that service is running. Not all rc scripts have a `status` option. For example: 
  572: 
  573: 
  574:     # /etc/rc.d/sshd status                                                      
  575:     sshd is not running.
  576:     # /etc/rc.d/sshd start
  577:     # /etc/rc.d/sshd status                                                    
  578:     sshd is running as pid 383.
  579:     # /etc/rc.d/sshd stop
  580:     
  581: 
  582:   
  583: Note that while every script in `/etc/rc.d` is _supposed_ to accept the `status` argument, many do not. 
  584: 
  585: If a service is not running, it can be started by executing its [rc(8)](http://netbsd.gw.com/cgi-bin/man-cgi?rc++NetBSD-current) script with an argument of `start`. Once a service is running, it can be restarted or stopped in a similar manner, using the arguments `restart` and `stop`. 
  586: 
  587: 
  588: Note that an rc script can not launch a service if this service is not marked as runable in `/etc/rc.conf` (via `service=YES` entry). 
  589: 
  590: ##  Configure a service to start at boot time 
  591: 
  592: Add or copy the rc skript to /etc/rc.d/ and then add the service to your /etc/rc.conf 
  593: 
  594: ##  View and configure system hardware 
  595: 
  596: View pci bus (use pci0 - 2) 
  597:     
  598:     $ pcictl /dev/pci0 list
  599:     
  600: 
  601: ##  View, load, or unload a kernel module 
  602: 
  603: View 
  604:     
  605:     $ modstat
  606:     
  607: 
  608: Load 
  609:     
  610:     # modload file
  611:     
  612: 
  613: Unload 
  614:     
  615:     # modunload -i id
  616:     
  617: 
  618: See the manual page for lkm.conf(5) for information on how to automatically load modules at boot time. Please note that for this to work, lkm=YES must be set in /etc/rc.conf. Also note the critical_filesystems_local setting in rc.conf(5), which may be required for bootloaded modules located under /usr if /usr is on a separate partition than /. 
  619: 
  620: ##  Modify a kernel parameter on the fly 
  621:     
  622:     # sysctl -w <variable>=<value>
  623:     
  624: 
  625: ##  View the status of a software RAID mirror or stripe 
  626: 
  627: Verify parity: 
  628:     
  629:     # raidctl -p raid0
  630:     /dev/rraid0c: Parity status: clean
  631:     
  632: 
  633: View configuration and state: 
  634:     
  635:     # raidctl -s raid0
  636:     
  637: 
  638: [raidctl(8)](http://netbsd.gw.com/cgi-bin/man-cgi?raidctl++NetBSD-current) man page is very useful, don't miss it. 
  639: 
  640: ##  Configure system logging 
  641: 
  642: Verify that [syslogd(8)](http://netbsd.gw.com/cgi-bin/man-cgi?syslogd++NetBSD-current) is running. If not, enable it in `/etc/rc.conf` and launch it: 
  643:     
  644: 
  645:     # /etc/rc.d/syslogd start
  646:     
  647: 
  648: The logging daemon is configured with `/etc/syslog.conf` (see [syslog.conf(5)](http://netbsd.gw.com/cgi-bin/man-cgi?syslog.conf++NetBSD-current). When you have modified this file, you have to tell to the daemon to reread it: 
  649:     
  650: 
  651:     # pkill -HUP syslogd 
  652:     
  653: 
  654: by sending a `SIGHUP`. 
  655: 
  656: If you add files in `/etc/syslog.conf`, don't forget to configure rotation in `/etc/newsyslog.conf` ([newsyslog.conf(5)](http://netbsd.gw.com/cgi-bin/man-cgi?newsyslog.conf++NetBSD-current)). 
  657: 
  658: 
  659: If the original daemon's filtering features are too poor for you, try [sysutils/syslog-ng](http://pkgsrc.se/sysutils/syslog-ng) package. 
  660: 
  661: To log signals sent to processes: 
  662:     
  663:     # sysctl -w kern.logsigexit=1
  664:     
  665: 
  666: ##  Review log files to troubleshoot and monitor system behavior 
  667:     
  668:     $ tail -f /var/log/messages |grep daemon
  669:     
  670: 
  671: Try also these packages: 
  672: 
  673:   * [misc/root-tail](http://pkgsrc.se/misc/root-tail) or [misc/xtail](http://pkgsrc.se/misc/xtail) if you use X11, 
  674:   * [misc/colortail](http://pkgsrc.se/misc/colortail) or [misc/mail](http://pkgsrc.se/misc/mtail) if you want colors, 
  675:   * [sysutils/wtail](http://pkgsrc.se/sysutils/wtail) or [misc/multitail](http://pkgsrc.se/misc/multitail) to view multiples files. 
  676: 
  677: ##  Determine which MTA is being used on the system 
  678:     
  679:     $ less /etc/mailer.conf
  680:     
  681: 
  682: ##  Create or modify email aliases for Sendmail or Postfix 
  683: 
  684: ##  View the Sendmail or Postfix mail queue 
  685:     
  686:     $ mailq
  687:     
  688: 
  689: ##  Read mail on the local system 
  690:     
  691:     $ mail
  692:     
  693: 
  694: ##  Understand basic printer troubleshooting 
  695: 
  696: ##  Halt, reboot, or bring the system to single-user mode 
  697: 
  698: to halt enter: 
  699:     
  700:     # shutdown -h now
  701:     
  702: 
  703: to reboot enter either: 
  704:     
  705:     # reboot
  706:     
  707: 
  708: or 
  709:     
  710:     # shutdown -r now
  711:     
  712: 
  713: to bring the system to single-user mode press any key during boot countdown and then enter: 
  714:     
  715:     boot -s
  716:     
  717: 
  718: From multi-user mode, you should: 
  719:     
  720:     # kill -TERM 1
  721:     
  722: 
  723: to return to single-user mode. 
  724: 
  725: ##  Recognize the difference between hard and soft limits and modify existing resource limits 
  726: 
  727: ##  Recognize common, possibly third-party, server configuration files 
  728: 
  729: ##  Configure the scripts that run periodically to perform various system maintenance tasks 
  730: 
  731: ##  Determine the last system boot time and the workload on the system 
  732:     
  733:     $ uptime
  734:     
  735: 
  736: or 
  737:     
  738:     $ w
  739:     
  740: 
  741: ##  Monitor disk input/output 
  742:     
  743:     $ iostat -w 1
  744:     
  745: 
  746: ##  Deal with busy devices 
  747: 
  748: ##  Determine information regarding the operating system 
  749:     
  750:     $ uname -a
  751:     
  752: 
  753: ##  Understand the advantages of using a BSD license 
  754: 
  755: #  Network Administration 
  756: 
  757: ##  Determine the current TCP/IP settings on a system 
  758: 
  759: First, see the interfaces which are connected: 
  760:     
  761:     $ ifconfig -ls
  762:     wm0 wm1 wm2 wm3 wm4 lo0 pflog0 vlan0 vlan1 vlan2 vlan3
  763:     
  764: 
  765: To see the IP adress of an interface: 
  766:     
  767:     $ ifconfig vlan3
  768:     vlan3: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
  769:            vlan: 847 parent: wm4
  770:            address: 00:04:23:af:f1:e4
  771:            inet 172.17.13.254 netmask 0xfffffe00 broadcast 172.17.13.255
  772:     
  773: 
  774: We have the MAC (hardware adress, here `00:04:23:af:f1:e4`) and the IP adress with netmask (here `172.17.13.254` with `255.255.254.0`). 
  775: 
  776: Now, we want to know IPv4 routing settings: 
  777:     
  778:     $ netstat -rn -f inet | head -5
  779:     Routing tables
  780:     
  781:     Internet:
  782:     Destination        Gateway            Flags    Refs      Use    Mtu  Interface
  783:     default            172.16.200.130     UG1         0  9607369      -  wm0
  784:     
  785: 
  786: The default route is tagged `default`, here it is `172.16.200.130` on `wm0` interface. 
  787: 
  788: See [ifconfig(8)](http://netbsd.gw.com/cgi-bin/man-cgi?ifconfig+8+NetBSD-current) and [netstat(8)](http://netbsd.gw.com/cgi-bin/man-cgi?netstat+8+NetBSD-current) for more details. 
  789: 
  790: ##  Set a system's TCP/IP settings 
  791:     
  792:     # ifconfig fxp0 192.168.0.1 netmask 255.255.255.0 up
  793:     
  794: 
  795: ##  Determine which TCP or UDP ports are open on a system 
  796:     
  797:     $ sockstat -cl
  798:     
  799: 
  800: ##  Verify the availability of a TCP/IP service 
  801:     
  802:     $ sockstat -l
  803:     
  804: 
  805: ##  Query a DNS server 
  806: 
  807: Find responsible nameservers for a given domain 
  808:     
  809:     $ dig ns netbsd.org
  810:     
  811: 
  812: Query a DNS server 
  813:     
  814:     $ dig @adns1.berkeley.edu A www.netbsd.org
  815:     
  816: 
  817: ##  Determine who is responsible for a DNS zone 
  818: 
  819: Use [dig(1)](http://netbsd.gw.com/cgi-bin/man-cgi?dig+1+NetBSD-current) to check the SOA section: 
  820:     
  821: 
  822: $ dig www.netbsd.org soa
  823:     ; <<>> DiG 9.3.2 <<>> www.netbsd.org soa
  824:     ;; global options:  printcmd
  825:     ;; Got answer:
  826:     ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 22618
  827:     ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0
  828:     
  829:     ;; QUESTION SECTION:
  830:     ;www.netbsd.org.                        IN      SOA
  831:     
  832:     ;; AUTHORITY SECTION:
  833:     netbsd.org.             10800   IN      SOA     ns.netbsd.org. hostmaster.netbsd.org.  2007032701 21600 10800 2419200 86400
  834:     
  835:     ;; Query time: 163 msec
  836:     ;; SERVER: 191.168.1.1#53(191.168.1.1)
  837:     ;; WHEN: Sun Jul  1 11:56:27 2007
  838:     ;; MSG SIZE  rcvd: 92
  839:     
  840: 
  841: The master server is `ns.netbsd.org` and the responsible is `hostmaster [at] netbsd [dot] org`. 
  842: 
  843: ##  Change the order of name resolution 
  844: 
  845: You live in `home.org` but you often work on hosts in `work.com`. To avoid typing FQDN all the time, put this in `/etc/resolv.conf`: 
  846:     
  847:     nameserver 1.2.3.4
  848:     nameserver 5.6.7.8
  849:     domain home.org
  850:     search home.org work.com
  851:     
  852: 
  853: The first two lines say which DNS servers to use. The third says that the resolver has to search host first in `home.org`. The last tells it search also in `work.com`. After that, you should have: 
  854:     
  855:     $ host www
  856:     www.work.com has address 192.168.1.2
  857:     
  858: 
  859: ##  Convert a subnet mask between dotted decimal, hexadecimal or CIDR notation 
  860: 
  861: Use either: 
  862: 
  863:   * [net/ipcalc](http://pkgsrc.se/net/ipcalc)
  864:   * [net/cidr](http://pkgsrc.se/net/cidr)
  865:   * [net/sipcalc](http://pkgsrc.se/net/sipcalc)
  866: 
  867: 
  868: ##  Gather information using an IP address and subnet mask 
  869: 
  870: ##  Understand IPv6 address theory 
  871: 
  872: ##  Demonstrate basic tcpdump(1) skills 
  873:     
  874:     # tcpdump -i fxp0 not port 22
  875:     
  876: 
  877: ##  Manipulate ARP and neighbor discovery caches 
  878: 
  879: View ARP cache 
  880:     
  881:     $ arp -a
  882:     
  883: 
  884: ##  Configure a system to use NTP 
  885: 
  886:   * Edit `/etc/ntp.conf` and choose from the list at least two servers, or add two new ones. The time servers should be located as close as possible (network topology) to your server. 
  887: 
  888:   * Add `ntpd=yes` to `/etc/rc.conf`
  889: 
  890:   * Start the ntp daemon by entering: `/etc/rc.d/ntpd start`
  891: 
  892:   * Verify the service, by entering `ntpq` and then `peers`. 
  893: 
  894: ##  View and renew a DHCP lease 
  895: 
  896: Renew a DHCP lease 
  897:     
  898:     # dhcpcd -k
  899:     # dhcpcd
  900:     
  901: 
  902: ##  Recognize when and how to set or remove an interface alias 
  903: 
  904: set alias 
  905:     
  906:     # ifconfig fxp0 inet 192.168.0.2 netmask 255.255.255.0 alias
  907:     
  908: 
  909: remove alias 
  910:     
  911:     # ifconfig fxp0 inet 192.168.0.2 netmask 255.255.255.0 -alias
  912:     
  913: 
  914: #  Basic Unix Skills 
  915: 
  916: ##  Demonstrate proficiency in using redirection, pipes and tees 
  917: 
  918: ###  Output redirection 
  919:     
  920:     $ ls > myfiles.txt
  921:     
  922: 
  923: runs `ls` and redirects the output in the file myfiles.txt 
  924:     
  925:     $ ls >> myfiles.txt
  926:     
  927: 
  928: runs `ls` and appends the output to the file myfiles.txt 
  929: 
  930: ###  Pipes 
  931:     
  932:     $ ls -l | wc -l
  933:     
  934: 
  935: runs `ls -l` and uses its output as the input for the command `wc -l`
  936: 
  937: ##  Recognize, view and modify environmental variables 
  938: 
  939: ###  Viewing environmental variables 
  940: 
  941: On sh based shells like sh, ksh, bash this is done with the command `export`
  942:     
  943:     $ export
  944:     
  945: 
  946: On csh, tcsh with `env`
  947:     
  948:     $ env
  949:     
  950: 
  951: ###  Modifying environmental variables 
  952: 
  953: On sh based shells you assign the variable on the left side the value on the right side using an equal sign. 
  954:     
  955:     $ export MYVAR="hello kitty"
  956:     
  957: 
  958: On csh, tcsh to assign use a single space instead of an equal sign. 
  959:     
  960:     $ setenv MYVAR "hello kitty"
  961:     
  962: 
  963: ##  Be familiar with the vi(1) editor 
  964: 
  965: hjkl movement 
  966: 
  967: i insert 
  968: 
  969: 0 beginning of line 
  970: 
  971: $ end of line 
  972: 
  973: o/O insert new line 
  974: 
  975: x/X delete char 
  976: 
  977: w/W Word 
  978: 
  979: e/E End of word 
  980: 
  981: b/B begin of word 
  982: 
  983: dd delete a line 
  984: 
  985: yy yank a line 
  986: 
  987: ##  Determine if a file is a binary, text, or data file 
  988: 
  989: The [file(1)](http://netbsd.gw.com/cgi-bin/man-cgi?file++NetBSD-current) command is capable of discerning between executable (binary) files, text files and data files. In many cases it is able to determine further information about data files, e.g. it can recognise image files as being GIFs or JPGs. 
  990:     
  991: 
  992: $ file /bin/sh
  993:     /bin/sh: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), for NetBSD 4.99.72, dynamically linked (uses shared libs), not stripped
  994:     
  995:     
  996:     $ file /etc/wscons.conf
  997:     /etc/wscons.conf: ASCII English text
  998:     
  999:     
 1000:     $  file AnsweringMachine.ogg
 1001:     AnsweringMachine.ogg: Ogg data, Vorbis audio, stereo, 44100 Hz, ~256000 bps, created by: Xiph.Org libVorbis I (1.1.0 RC1)
 1002:     
 1003:     
 1004:     $ file photo.jpg
 1005:     photo.jpg: JPEG image data, JFIF standard 1.01
 1006:     
 1007: 
 1008: ##  Locate files and binaries on a system 
 1009: 
 1010: Binaries 
 1011:     
 1012:     $ whereis netstat
 1013:     
 1014: 
 1015: ##  Overcome command line length limitations 
 1016: 
 1017: ##  Find a file with a given set of attributes 
 1018: 
 1019: ##  Create a simple Bourne shell script 
 1020:     
 1021:     vi myshellscript.sh
 1022:     
 1023: 
 1024: ##  Find appropriate documentation 
 1025:     
 1026:     $ apropos keyword
 1027:     $ man command
 1028:     
 1029: 
 1030: ##  Recognize the different sections of the manual 
 1031: 
 1032: Sections are from 1 to 9 
 1033: 
 1034:   * 1 General commands manual 
 1035:     
 1036:     $ man 1 df
 1037:     
 1038: 
 1039:   * 2 System calls manual 
 1040:     
 1041:     $ man 2 lseek
 1042:     
 1043: 
 1044:   * 3 Library functions manual 
 1045:     
 1046:     $ man 3 sprintf
 1047:     
 1048: 
 1049:   * 4 Kernel interfaces manual 
 1050:     
 1051:     $ man 4 null
 1052:     
 1053: 
 1054:   * 5 File formats manual 
 1055:     
 1056:     $ man 5 exports
 1057:     
 1058: 
 1059:   * 6 Games manual 
 1060:     
 1061:     $ man 6 tetris
 1062:     
 1063: 
 1064:   * 7 Miscellanea 
 1065:     
 1066:     $ man 7 me
 1067:     
 1068: 
 1069:   * 8 System manager's manual 
 1070:     
 1071:     $ man 8 reboot
 1072:     
 1073: 
 1074:   * 9 Kernel developer's manual 
 1075:     
 1076:     $ man 9 kauth
 1077:     
 1078: 
 1079: ##  Verify a file's message digest fingerprint (checksum) 
 1080: 
 1081: Depending on what sort of digest is used enter either: 
 1082:     
 1083:     $ md5 _filename_
 1084:     
 1085: 
 1086: or 
 1087:     
 1088:     $ sha1 _filename_
 1089:     
 1090: 
 1091: and compare the output. 
 1092: 
 1093: ##  Demonstrate familiarity with the default shell 
 1094: 
 1095: ##  Use job control 
 1096: 
 1097: List jobs 
 1098:     
 1099:     $ jobs -l
 1100:     
 1101: 
 1102: Put job into background 
 1103:     
 1104:     # /usr/libexec/locate.updatedb &
 1105:     
 1106: 
 1107: Put job into foreground 
 1108:     
 1109:     # fg pid
 1110:     
 1111: 
 1112: Put job into background 
 1113:     
 1114:     # bg pid
 1115:     
 1116: 
 1117: ##  Demonstrate proficiency with regular expressions 
 1118: 
 1119: ##  Understand various "domain" contexts 
 1120: 
 1121: ##  Configure an action to be scheduled by cron(8) 
 1122: 
 1123: There are two ways to accomplish this task. You either put the cronjob in the global crontab file `/etc/crontab` or you edit your own crontab with `crontab -e`. 
 1124:     
 1125:     $ crontab -e
 1126:     
 1127: 
 1128: (this command invokes your favorite text editor specified by `$EDITOR` environment variable or `VISUAL`, by default `/usr/bin/vi`). 
 1129: 
 1130: Add a cronjob: 
 1131:     
 1132:     0 23 * * *     sh /my/home/shellskript
 1133:     
 1134: 
 1135: Here, the script will be run all days at 23:00. The fields order is minute, hour, day of month, month and day of week; the last field is the command to run. See [crontab(5)](http://netbsd.gw.com/cgi-bin/man-cgi?crontab+5+NetBSD-current) for details. List your current crontab: 
 1136:     
 1137: 
 1138: $ crontab -l
 1139:     
 1140: 
 1141: As root you can see and edit any users crontab by supplying `-u` username 
 1142:     
 1143:     # crontab -l -u john
 1144:     
 1145: 
 1146: or edit it 
 1147:     
 1148:     # crontab -e -u john
 1149:     
 1150: 
 1151: When using the global `/etc/crontab` you have to supply the user who is executing the cronjob: 
 1152:     
 1153:     # vi /etc/crontab
 1154:     0 22 * * *    john    sh /johns/work/shellskript
 1155:     
 1156: 

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