netbsd-tips revision 1.9
11.1SreedList 20 largest files (larger than 5 MB) sorted by megabytes: 21.1Sreed 31.1Sreed find / -type f -size +10000 -print0 | xargs -0 du -m | sort -nr | head -20 41.1Sreed% 51.1SreedYou can keep specific rc.conf configurations in individual files 61.1Sreedunder /etc/rc.conf.d/ where each file is named after the $name of 71.1Sreedthe rc.d script. Some configurations may have different names than 81.1Sreedthe script; see the $name variable to check. 91.1Sreed% 101.1SreedYou can see the total used buffers in megabytes with: 111.1Sreed 121.1Sreed vmstat -s | awk ' 131.1Sreed/ bytes per page$/ { bpp = $1 } 141.1Sreed/ cached file pages$/ { cfp = $1 } 151.1Sreed/ cached executable pages$/ { cep = $1 } 161.1SreedEND { print((cfp + cep) * bpp / 1024 / 1024); }' 171.1Sreed% 181.1SreedYou can view a value of a variable in pkgsrc by using the show-var 191.1Sreedtarget, for example: 201.1Sreed 211.1Sreed make show-var VARNAME=MAINTAINER 221.1Sreed% 231.1SreedYou can view the basic order of your rc.d scripts with: 241.1Sreed 251.1Sreed rcorder /etc/rc.d/* 261.1Sreed% 271.1SreedYou can ask questions about NetBSD at the netbsd-users@NetBSD.org 281.1Sreedmailing list. Be sure to clearly explain your problem, what you 291.1Sreedtried, what results you had, and what you expected. 301.1Sreed% 311.1SreedYou can view your non-default Postfix settings with: 321.1Sreed 331.1Sreed postconf -n 341.1Sreed% 351.1SreedTo report about installed packages with known vulnerabilities, 361.1Sreedfetch the latest pkg-vulnerabilities file as the superuser with: 371.1Sreed 381.8Sleot pkg_admin fetch-pkg-vulnerabilities 391.1Sreed 401.1SreedAnd then run: 411.1Sreed 421.8Sleot pkg_admin audit 431.1Sreed% 441.1SreedThe following shows an example of temporarily adding 10MB more swap 451.1Sreedspace for virtual memory: 461.1Sreed 471.3Sreed dd if=/dev/zero of=/root/swapfile bs=1024 count=10240 481.3Sreed chmod go= /root/swapfile 491.1Sreed swapctl -a /root/swapfile 501.1Sreed% 511.1SreedIf your console ever gets broken, you can try resetting it to its 521.1Sreedinitial state with: 531.1Sreed 541.7Sleot printf "\033c" 551.1Sreed% 561.1SreedIf you installed a package, but don't know what the software is 571.5Swizcalled or what executables to run, use pkg_info with the -L switch 581.5Swizto list the package's files and search for /bin: 591.1Sreed 601.5Swiz pkg_info -L PACKAGE-NAME | grep /bin 611.1Sreed% 621.1SreedA new user can be added by using the useradd tool with the -m switch 631.1Sreedto create the home directory. Then set the password. For example: 641.1Sreed 651.1Sreed useradd -m susan 661.1Sreed passwd susan 671.1Sreed% 681.1SreedTo modify user account information use the chpass or usermod tools. 691.1SreedIf you need to edit the user database directly, use the vipw command. 701.1Sreed% 711.1SreedYou can temporarily start the SSH server by running the following 721.1Sreedas root: 731.1Sreed 741.1Sreed /etc/rc.d/sshd onestart 751.1Sreed% 761.6SmaxvSeveral NPF examples are available in the /usr/share/examples/npf/ 771.6Smaxvdirectory. 781.1Sreed% 791.1SreedWant to dual boot using a bluetooth mouse or keyboard? Use btkey(1) 801.1Sreedto store the link key in the hardware. 811.1Sreed% 821.1SreedIf you are having trouble connecting to a remote bluetooth device, 831.1Sreedtry the btconfig(8) inquiry command. The kernel will retain some 841.1Sreedclock offset information that may help. 851.1Sreed% 861.1SreedYou can download files via HTTP using the ftp(1) command; for example: 871.1Sreed 881.1Sreed ftp http://www.NetBSD.org/images/NetBSD.png 891.1Sreed% 901.1SreedThe mtree(8) tool can be used to check permissions, ownerships, 911.1Sreedfile changes, and more when compared against a specification. For 921.1Sreedexample to check directory ownership and permissions for standard 931.1SreedNetBSD directories, run: 941.1Sreed 951.1Sreed /usr/sbin/mtree -e -p / -f /etc/mtree/NetBSD.dist 961.1Sreed% 971.1SreedIf you need reminders on your console to leave, use the leave(1) 981.1Sreedtool. For example to receive reminders to leave in one hour: 991.1Sreed 1001.1Sreed leave +0100 1011.1Sreed% 1021.1SreedTo stop non-superuser logins until next boot, as root: 1031.1Sreed 1041.1Sreed touch /etc/nologin 1051.1Sreed% 1061.1SreedWhen extracting distribution tar sets, be sure to use the pax -pe 1071.1Sreedoption or the tar -p switch to preserve the user and group and file 1081.1Sreedmodes (including setuid and setgid). This is needed, for example, 1091.1Sreedso su(1) will work after extracting the base.tgz set. 1101.1Sreed% 1111.1SreedMath can be done within the sh(1) and ksh(1) shells or with expr(1), 1121.1Sreeddc(1), bc(1), or awk(1). Here are some simple examples: 1131.1Sreed 1141.1Sreed echo $((431 * 79)) 1151.1Sreed expr 60 \* 60 \* 24 \* 7 1161.1Sreed% 1171.2SreedYou can view network connections with the fstat, netstat -a, sockstat, 1181.2Sreedand "systat netstat" commands. 1191.2Sreed% 1201.2SreedVisit the NetBSD Security website to keep track of advisories: 1211.2Sreed http://www.NetBSD.org/support/security/ 1221.2SreedOr join the security-announce mailing list for alerts: 1231.2Sreed http://www.netbsd.org/mailinglists/#security-announce 1241.2Sreed% 1251.2SreedHere's an example of finding what package a file belongs to: 1261.2Sreed 1271.2Sreed pkg_info -Fe /usr/pkg/bin/inw 1281.2Sreed% 1291.2SreedMany log files are checked for rotation every hour by newsyslog(8). 1301.2SreedIt is configured in /etc/newsyslog.conf. 1311.2Sreed% 1321.2SreedNetBSD's default cron jobs are defined in the /var/cron/tabs/root 1331.2Sreedfile. As the superuser, use "crontab -l" to view it. To edit it, 1341.2Sreeduse "crontab -e" (which defaults to using the vi(1) editor). 1351.2Sreed% 1361.4SjmmvYou can make sure that your system is stable and behaves correctly by 1371.4Sjmmvrunning the tests in /usr/tests (which come from the tests.tgz set). 1381.4SjmmvTo do so: 1391.4Sjmmv 1401.4Sjmmv vi /etc/atf/NetBSD.conf 1411.4Sjmmv cd /usr/tests 1421.4Sjmmv atf-run | atf-report 1431.4Sjmmv% 1441.9SniaTo share files from your NetBSD system, you can use the built-in 1451.9Sniahttpd(8). Uncomment the 'http' lines in /etc/inetd.conf, reload inetd 1461.9Sniawith service(8), and then any files in /var/www will be published to 1471.9Sniahttp://127.0.0.1/. 1481.9Snia% 1491.9SniaYou can schedule simple periodic tasks for your NetBSD system to run 1501.9Sniawithout using cron(8) by editing the sh(1) scripts /etc/daily.local, 1511.9Snia/etc/weekly.local, and /etc/monthly.local. 1521.9Snia% 1531.9SniaNetBSD's tar(1) command can handle a wide range of file types, e.g. 1541.9Sniazip, 7z, and rar, and will autodetect the type of the file based 1551.9Sniaon its extension. For example, to extract a zip file: 1561.9Snia 1571.9Snia tar xvf example.zip 1581.9Snia% 1591.9SniaYou can use progress(1) to monitor the progress of data in a pipe: 1601.9Snia 1611.9Snia zcat example.tar.gz | progress tar xf - 162