BOOK/chapter08/systemd.xml

   1 <?xml version="1.0" encoding="ISO-8859-1"?>
   2 <!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   3   "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
   4   <!ENTITY % general-entities SYSTEM "../general.ent">
   5   %general-entities;
   6 ]>
   7
   8 <sect1 id="ch-system-systemd" role="wrap" revision="systemd">
   9   <?dbhtml filename="systemd.html"?>
  10
  11   <sect1info condition="script">
  12     <productname>systemd</productname>
  13     <productnumber>&systemd-version;</productnumber>
  14     <address>&systemd-url;</address>
  15   </sect1info>
  16
  17   <title>Systemd-&systemd-version;</title>
  18
  19   <indexterm zone="ch-system-systemd">
  20     <primary sortas="a-systemd">systemd</primary>
  21   </indexterm>
  22
  23   <sect2 role="package">
  24     <title/>
  25
  26     <para>The systemd package contains programs for controlling the startup,
  27     running, and shutdown of the system.</para>
  28
  29     <segmentedlist>
  30       <segtitle>&buildtime;</segtitle>
  31       <segtitle>&diskspace;</segtitle>
  32
  33       <seglistitem>
  34         <seg>&systemd-fin-sbu;</seg>
  35         <seg>&systemd-fin-du;</seg>
  36       </seglistitem>
  37     </segmentedlist>
  38   </sect2>
  39
  40   <sect2 role="installation">
  41     <title>Installation of systemd</title>
  42
  43 <!--
  44     <para>First, apply a patch to fix the build with GCC-10 and fix a segfault:</para>
  45
  46 <screen><userinput remap="pre">patch -Np1 -i ../systemd-&systemd-version;-gcc_10-fixes-2.patch</userinput></screen>
  47 -->
  48
  49     <para>First, apply a patch to fix some regressions:</para>
  50
  51 <screen><userinput remap="pre">patch -Np1 -i ../systemd-&systemd-version;-upstream_fixes-1.patch</userinput></screen>
  52
  53     <para>Create a symlink to work around the xsltproc command not being installed:</para>
  54
  55 <screen><userinput remap="pre">ln -sf /bin/true /usr/bin/xsltproc</userinput></screen>
  56
  57     <para>Set up the man pages:</para>
  58
  59 <screen><userinput remap="pre">tar -xf ../systemd-man-pages-&systemd-version;.tar.xz</userinput></screen>
  60
  61     <para>Remove tests that cannot be built in chroot:</para>
  62
  63 <screen><userinput remap="pre">sed '181,$ d' -i src/resolve/meson.build</userinput></screen>
  64
  65     <para>Remove an unneeded group,
  66     <systemitem class="groupname">render</systemitem>, from the default udev
  67     rules:</para>
  68
  69 <screen><userinput remap="pre">sed -i 's/GROUP="render", //' rules.d/50-udev-default.rules.in</userinput></screen>
  70
  71     <para>Prepare systemd for compilation:</para>
  72
  73 <screen><userinput remap="configure">mkdir -p build
  74 cd       build
  75
  76 LANG=en_US.UTF-8                    \
  77 meson --prefix=/usr                 \
  78       --sysconfdir=/etc             \
  79       --localstatedir=/var          \
  80       -Dblkid=true                  \
  81       -Dbuildtype=release           \
  82       -Ddefault-dnssec=no           \
  83       -Dfirstboot=false             \
  84       -Dinstall-tests=false         \
  85       -Dkmod-path=/bin/kmod         \
  86       -Dldconfig=false              \
  87       -Dmount-path=/bin/mount       \
  88       -Drootprefix=                 \
  89       -Drootlibdir=/lib             \
  90       -Dsplit-usr=true              \
  91       -Dsulogin-path=/sbin/sulogin  \
  92       -Dsysusers=false              \
  93       -Dumount-path=/bin/umount     \
  94       -Db_lto=false                 \
  95       -Drpmmacrosdir=no             \
  96       -Dhomed=false                 \
  97       -Duserdb=false                \
  98       -Dman=true                    \
  99       -Dmode=release                \
 100       -Ddocdir=/usr/share/doc/systemd-&systemd-version; \
 101       ..</userinput></screen>
 102
 103     <variablelist>
 104       <title>The meaning of the meson options:</title>
 105
 106       <varlistentry>
 107         <term><parameter>-D*-path=*</parameter></term>
 108         <listitem>
 109           <para>These switches provide the location of binaries needed by
 110           systemd at runtime that have not yet been installed.</para>
 111         </listitem>
 112       </varlistentry>
 113
 114       <varlistentry>
 115         <term><parameter>-Ddefault-dnssec=no</parameter></term>
 116         <listitem>
 117           <para>This switch turns off the experimental DNSSEC support.</para>
 118         </listitem>
 119       </varlistentry>
 120
 121       <varlistentry>
 122         <term><parameter>-Dfirstboot=false</parameter></term>
 123         <listitem>
 124           <para>This switch prevents installation of systemd
 125           services responsible for setting up the system for
 126           the first time. They are not useful for LFS because
 127           everything is done manually.</para>
 128         </listitem>
 129       </varlistentry>
 130
 131       <varlistentry>
 132         <term><parameter>-Dinstall-tests=false</parameter></term>
 133         <listitem>
 134           <para>This switch prevents installation of the compiled tests.</para>
 135         </listitem>
 136       </varlistentry>
 137
 138       <varlistentry>
 139         <term><parameter>-Dldconfig=false</parameter></term>
 140         <listitem>
 141           <para>This switch prevents installation of a systemd unit that runs
 142           <command>ldconfig</command> at boot, which is not useful for source
 143           distributions such as LFS and makes the boot time longer. Remove it
 144           if the described feature is desired.</para>
 145         </listitem>
 146       </varlistentry>
 147
 148       <varlistentry>
 149         <term><parameter>-Droot*</parameter></term>
 150         <listitem>
 151           <para>These switches ensure that core programs and
 152           shared libraries are installed in subdirectories
 153           of the root partition.</para>
 154         </listitem>
 155       </varlistentry>
 156
 157       <varlistentry>
 158         <term><parameter>-Dsplit-usr=true</parameter></term>
 159         <listitem>
 160           <para>This switch ensures that systemd will work on
 161           systems where /bin, /lib and /sbin directories are not
 162           symlinks to their /usr counterparts.</para>
 163         </listitem>
 164       </varlistentry>
 165
 166       <varlistentry>
 167         <term><parameter>-Dsysusers=false</parameter></term>
 168         <listitem>
 169           <para>This switch prevents installation of systemd
 170           services responsible for setting up the
 171           <filename>/etc/group</filename> and
 172           <filename>/etc/passwd</filename> files. Both files
 173           were created earlier in this chapter.</para>
 174         </listitem>
 175       </varlistentry>
 176
 177       <varlistentry>
 178         <term><parameter>-Drpmmacrosdir=no</parameter></term>
 179         <listitem>
 180           <para>This switch disables installation of RPM Macros
 181           for use with systemd because LFS does not support RPM.</para>
 182         </listitem>
 183       </varlistentry>
 184
 185       <varlistentry>
 186         <term><parameter>-D{userdb,homed}=false</parameter></term>
 187         <listitem>
 188           <para>Remove two daemons that have dependencies that do not fit
 189           the scope of LFS.</para>
 190         </listitem>
 191       </varlistentry>
 192
 193       <varlistentry>
 194         <term><parameter>-Dmode=release</parameter></term>
 195         <listitem>
 196           <para>Disable some features considered experimental by upstream.
 197           </para>
 198         </listitem>
 199       </varlistentry>
 200
 201     </variablelist>
 202
 203     <para>Compile the package:</para>
 204
 205 <screen><userinput remap="make">LANG=en_US.UTF-8 ninja</userinput></screen>
 206
 207     <para>Install the package:</para>
 208
 209 <screen><userinput remap="install">LANG=en_US.UTF-8 ninja install</userinput></screen>
 210
 211     <para>Remove an unnecessary symbolic link:</para>
 212
 213 <screen><userinput remap="install">rm -f /usr/bin/xsltproc</userinput></screen>
 214
 215     <para>Create the <filename>/etc/machine-id</filename> file needed by
 216     <command>systemd-journald</command>:</para>
 217
 218 <screen><userinput remap="adjust">systemd-machine-id-setup</userinput></screen>
 219
 220     <para>Setup the basic target structure:</para>
 221
 222 <screen><userinput remap="adjust">systemctl preset-all</userinput></screen>
 223
 224     <para>Disable a service that is known to cause problems with systems that
 225     use a network configuration other than what is provided by
 226     systemd-networkd:</para>
 227     <!-- Observed halting startup with dhcpcd handling the primary NIC -->
 228
 229 <screen><userinput remap="adjust">systemctl disable systemd-time-wait-sync.service</userinput></screen>
 230
 231     <para>Prevent systemd from resetting the maximum PID value which causes
 232     some problems with packages and units in BLFS:</para>
 233
 234 <screen><userinput remap="adjust">rm -f /usr/lib/sysctl.d/50-pid-max.conf</userinput></screen>
 235
 236   </sect2>
 237
 238   <sect2 id="contents-systemd" role="content">
 239     <title>Contents of systemd</title>
 240
 241     <segmentedlist>
 242       <segtitle>Installed programs</segtitle>
 243       <segtitle>Installed libraries</segtitle>
 244       <segtitle>Installed directories</segtitle>
 245
 246       <seglistitem>
 247         <seg>bootctl, busctl, coredumpctl, halt (symlink to systemctl),
 248         hostnamectl, init, journalctl, kernel-install, localectl, loginctl,
 249         machinectl, networkctl, portablectl, poweroff (symlink to
 250         systemctl), reboot (symlink to systemctl), resolvconf (symlink to
 251         resolvectl), resolvectl, runlevel (symlink to systemctl), shutdown
 252         (symlink to systemctl), systemctl, systemd-analyze,
 253         systemd-ask-password, systemd-cat, systemd-cgls, systemd-cgtop,
 254         systemd-delta, systemd-detect-virt, systemd-dissect, systemd-escape,
 255         systemd-hwdb, systemd-id128, systemd-inhibit, systemd-machine-id-setup,
 256         systemd-mount, systemd-notify, systemd-nspawn, systemd-path,
 257         systemd-repart, systemd-resolve (symlink to resolvectl), systemd-run,
 258         systemd-socket-activate, systemd-stdio-bridge, systemd-tmpfiles,
 259         systemd-tty-ask-password-agent, systemd-umount (symlink to
 260         systemd-mount), telinit (symlink to systemctl), timedatectl, and
 261         udevadm</seg>
 262         <seg>libnss_myhostname.so.2, libnss_mymachines.so.2,
 263         libnss_resolve.so.2, libnss_systemd.so.2,
 264         libsystemd.so, libsystemd-shared-&systemd-version;.so (in /lib/systemd),
 265         and libudev.so</seg>
 266         <seg>/etc/binfmt.d, /etc/init.d, /etc/kernel, /etc/modules-load.d,
 267         /etc/sysctl.d, /etc/systemd, /etc/tmpfiles.d, /etc/udev,
 268         /etc/xdg/systemd, /lib/systemd, /lib/udev, /usr/include/systemd,
 269         /usr/lib/binfmt.d, /usr/lib/environment.d, /usr/lib/kernel,
 270         /usr/lib/modules-load.d, /usr/lib/sysctl.d, /usr/lib/systemd,
 271         /usr/lib/tmpfiles.d,
 272         /usr/share/doc/systemd-&systemd-version;, /usr/share/factory,
 273         /usr/share/systemd, /var/lib/systemd, and /var/log/journal</seg>
 274       </seglistitem>
 275     </segmentedlist>
 276
 277     <variablelist>
 278       <bridgehead renderas="sect3">Short Descriptions</bridgehead>
 279       <?dbfo list-presentation="list"?>
 280       <?dbhtml list-presentation="table"?>
 281
 282       <varlistentry id="bootctl">
 283         <term><command>bootctl</command></term>
 284         <listitem>
 285           <para>Is used to query the firmware and boot manager settings</para>
 286           <indexterm zone="ch-system-systemd bootctl">
 287             <primary sortas="b-bootctl">bootctl</primary>
 288           </indexterm>
 289         </listitem>
 290       </varlistentry>
 291
 292       <varlistentry id="busctl">
 293         <term><command>busctl</command></term>
 294         <listitem>
 295           <para>Is used to introspect and monitor the D-Bus bus</para>
 296           <indexterm zone="ch-system-systemd busctl">
 297             <primary sortas="b-busctl">busctl</primary>
 298           </indexterm>
 299         </listitem>
 300       </varlistentry>
 301
 302       <varlistentry id="coredumpctl">
 303         <term><command>coredumpctl</command></term>
 304         <listitem>
 305           <para>Is used to retrieve coredumps from the systemd journal</para>
 306           <indexterm zone="ch-system-systemd coredumpctl">
 307             <primary sortas="b-coredumpctl">coredumpctl</primary>
 308           </indexterm>
 309         </listitem>
 310       </varlistentry>
 311
 312       <varlistentry id="halt">
 313         <term><command>halt</command></term>
 314         <listitem>
 315           <para>Normally invokes <command>shutdown</command> with the
 316           <parameter>-h</parameter> option, except when already in run-level 0,
 317           then it tells the kernel to halt the system; it notes in the
 318           file <filename>/var/log/wtmp</filename> that the system is being
 319           brought down</para>
 320           <indexterm zone="ch-system-systemd halt">
 321             <primary sortas="b-halt">halt</primary>
 322           </indexterm>
 323         </listitem>
 324       </varlistentry>
 325
 326       <varlistentry id="hostnamectl">
 327         <term><command>hostnamectl</command></term>
 328         <listitem>
 329           <para>Is used to query and change the system hostname and related
 330           settings</para>
 331           <indexterm zone="ch-system-systemd hostnamectl">
 332             <primary sortas="b-hostnamectl">hostnamectl</primary>
 333           </indexterm>
 334         </listitem>
 335       </varlistentry>
 336
 337       <varlistentry id="init">
 338         <term><command>init</command></term>
 339         <listitem>
 340           <para>Is the first process to be started when the kernel has initialized
 341           the hardware which takes over the boot process and starts all
 342           processes according to its configuration files. In this case, it starts
 343           systemd.</para>
 344           <indexterm zone="ch-system-systemd init">
 345             <primary sortas="b-init">init</primary>
 346           </indexterm>
 347         </listitem>
 348       </varlistentry>
 349
 350       <varlistentry id="journalctl">
 351         <term><command>journalctl</command></term>
 352         <listitem>
 353           <para>Is used to query the contents of the systemd journal</para>
 354           <indexterm zone="ch-system-systemd journalctl">
 355             <primary sortas="b-journalctl">journalctl</primary>
 356           </indexterm>
 357         </listitem>
 358       </varlistentry>
 359
 360       <varlistentry id="kernel-install">
 361         <term><command>kernel-install</command></term>
 362         <listitem>
 363           <para>Is used to add and remove kernel and initramfs images to and
 364           from /boot. In LFS, this is done manually.</para>
 365           <indexterm zone="ch-system-systemd kernel-install">
 366             <primary sortas="b-kernel-install">kernel-install</primary>
 367           </indexterm>
 368         </listitem>
 369       </varlistentry>
 370
 371       <varlistentry id="localectl">
 372         <term><command>localectl</command></term>
 373         <listitem>
 374           <para>Is used to query and change the system locale and keyboard layout
 375           settings</para>
 376           <indexterm zone="ch-system-systemd localectl">
 377             <primary sortas="b-localectl">localectl</primary>
 378           </indexterm>
 379         </listitem>
 380       </varlistentry>
 381
 382       <varlistentry id="loginctl">
 383         <term><command>loginctl</command></term>
 384         <listitem>
 385           <para>Is used to introspect and control the state of the systemd Login
 386           Manager</para>
 387           <indexterm zone="ch-system-systemd loginctl">
 388             <primary sortas="b-loginctl">loginctl</primary>
 389           </indexterm>
 390         </listitem>
 391       </varlistentry>
 392
 393       <varlistentry id="machinectl">
 394         <term><command>machinectl</command></term>
 395         <listitem>
 396           <para>Is used to introspect and control the state of the systemd Virtual
 397           Machine and Container Registration Manager</para>
 398           <indexterm zone="ch-system-systemd machinectl">
 399             <primary sortas="b-machinectl">machinectl</primary>
 400           </indexterm>
 401         </listitem>
 402       </varlistentry>
 403
 404       <varlistentry id="networkctl">
 405         <term><command>networkctl</command></term>
 406         <listitem>
 407           <para>Is used to introspect and configure the state of the network
 408           links configured by systemd-networkd</para>
 409           <indexterm zone="ch-system-systemd networkctl">
 410             <primary sortas="b-networkctl">networkctl</primary>
 411           </indexterm>
 412         </listitem>
 413       </varlistentry>
 414
 415       <varlistentry id="portablectl">
 416         <term><command>portablectl</command></term>
 417         <listitem>
 418           <para>Is used to attach or detach portable services from the local
 419           system</para>
 420           <indexterm zone="ch-system-systemd portablectl">
 421             <primary sortas="b-portablectl">portablectl</primary>
 422           </indexterm>
 423         </listitem>
 424       </varlistentry>
 425
 426       <varlistentry id="poweroff">
 427         <term><command>poweroff</command></term>
 428         <listitem>
 429           <para>Instructs the kernel to halt the system and switch off the computer
 430           (see <command>halt</command>)</para>
 431           <indexterm zone="ch-system-systemd poweroff">
 432             <primary sortas="b-poweroff">poweroff</primary>
 433           </indexterm>
 434         </listitem>
 435       </varlistentry>
 436
 437       <varlistentry id="reboot">
 438         <term><command>reboot</command></term>
 439         <listitem>
 440           <para>Instructs the kernel to reboot the system (see
 441           <command>halt</command>)</para>
 442           <indexterm zone="ch-system-systemd reboot">
 443             <primary sortas="b-reboot">reboot</primary>
 444           </indexterm>
 445         </listitem>
 446       </varlistentry>
 447
 448       <varlistentry id="resolvconf">
 449         <term><command>resolvconf</command></term>
 450         <listitem>
 451           <para>Registers DNS server and domain configuration with
 452           <command>systemd-resolved</command></para>
 453           <indexterm zone="ch-system-systemd resolvconf">
 454             <primary sortas="b-resolvconf">resolvconf</primary>
 455           </indexterm>
 456         </listitem>
 457       </varlistentry>
 458
 459       <varlistentry id="resolvectl">
 460         <term><command>resolvectl</command></term>
 461         <listitem>
 462           <para>Sends control commands to the network name resolution
 463           manager, or resolves domain names, IPv4 and IPv6 addresses,
 464           DNS records, and services.</para>
 465           <indexterm zone="ch-system-systemd resolvectl">
 466             <primary sortas="b-resolvectl">resolvectl</primary>
 467           </indexterm>
 468         </listitem>
 469       </varlistentry>
 470
 471       <varlistentry id="runlevel">
 472         <term><command>runlevel</command></term>
 473         <listitem>
 474           <para>Outputs the previous and the current run-level, as noted in the
 475           last run-level record in <filename>/var/run/utmp</filename></para>
 476           <indexterm zone="ch-system-systemd runlevel">
 477             <primary sortas="b-runlevel">runlevel</primary>
 478           </indexterm>
 479         </listitem>
 480       </varlistentry>
 481
 482       <varlistentry id="shutdown">
 483         <term><command>shutdown</command></term>
 484         <listitem>
 485           <para>Brings the system down in a safe and secure manner, signaling
 486           all processes and notifying all logged-in users</para>
 487           <indexterm zone="ch-system-systemd shutdown">
 488             <primary sortas="b-shutdown">shutdown</primary>
 489           </indexterm>
 490         </listitem>
 491       </varlistentry>
 492
 493       <varlistentry id="systemctl">
 494         <term><command>systemctl</command></term>
 495         <listitem>
 496           <para>Is used to introspect and control the state of the systemd system
 497           and service manager</para>
 498           <indexterm zone="ch-system-systemd systemctl">
 499             <primary sortas="b-systemctl">systemctl</primary>
 500           </indexterm>
 501         </listitem>
 502       </varlistentry>
 503
 504       <varlistentry id="systemd-analyze">
 505         <term><command>systemd-analyze</command></term>
 506         <listitem>
 507           <para>Is used to determine system startup performance of the current
 508           boot, as well as identify troublesome systemd units</para>
 509           <indexterm zone="ch-system-systemd systemd-analyze">
 510             <primary sortas="b-systemd-analyze">systemd-analyze</primary>
 511           </indexterm>
 512         </listitem>
 513       </varlistentry>
 514
 515       <varlistentry id="systemd-ask-password">
 516         <term><command>systemd-ask-password</command></term>
 517         <listitem>
 518           <para>Is used to query a system password or passphrase from the user,
 519           using a question message specified on the command line</para>
 520           <indexterm zone="ch-system-systemd systemd-ask-password">
 521             <primary sortas="b-systemd-ask-password">systemd-ask-password</primary>
 522           </indexterm>
 523         </listitem>
 524       </varlistentry>
 525
 526       <varlistentry id="systemd-cat">
 527         <term><command>systemd-cat</command></term>
 528         <listitem>
 529           <para>Is used to connect the STDOUT and STDERR outputs of a process
 530           with the systemd journal.
 531           </para>
 532           <indexterm zone="ch-system-systemd systemd-cat">
 533             <primary sortas="b-systemd-cat">systemd-cat</primary>
 534           </indexterm>
 535         </listitem>
 536       </varlistentry>
 537
 538       <varlistentry id="systemd-cgls">
 539         <term><command>systemd-cgls</command></term>
 540         <listitem>
 541           <para>Recursively shows the contents of the selected Linux control
 542           group hierarchy in a tree</para>
 543           <indexterm zone="ch-system-systemd systemd-cgls">
 544             <primary sortas="b-systemd-cgls">systemd-cgls</primary>
 545           </indexterm>
 546         </listitem>
 547       </varlistentry>
 548
 549       <varlistentry id="systemd-cgtop">
 550         <term><command>systemd-cgtop</command></term>
 551         <listitem>
 552           <para>Shows the top control groups of the local Linux control group
 553           hierarchy, ordered by their CPU, memory and disk I/O load</para>
 554           <indexterm zone="ch-system-systemd systemd-cgtop">
 555             <primary sortas="b-systemd-cgtop">systemd-cgtop</primary>
 556           </indexterm>
 557         </listitem>
 558       </varlistentry>
 559
 560       <varlistentry id="systemd-delta">
 561         <term><command>systemd-delta</command></term>
 562         <listitem>
 563           <para>Is used to identify and compare configuration files in
 564           <filename class="directory">/etc</filename> that override default
 565           counterparts in <filename class="directory">/usr</filename></para>
 566           <indexterm zone="ch-system-systemd systemd-delta">
 567             <primary sortas="b-systemd-delta">systemd-delta</primary>
 568           </indexterm>
 569         </listitem>
 570       </varlistentry>
 571
 572       <varlistentry id="systemd-detect-virt">
 573         <term><command>systemd-detect-virt</command></term>
 574         <listitem>
 575           <para>Detects whether the system is being run in a virtual
 576           environment, and adjusts udev accordingly.</para>
 577           <indexterm zone="ch-system-systemd systemd-detect-virt">
 578             <primary sortas="b-systemd-detect-virt">systemd-detect-virt</primary>
 579           </indexterm>
 580         </listitem>
 581       </varlistentry>
 582
 583       <varlistentry id="systemd-dissect">
 584         <term><command>systemd-dissect</command></term>
 585         <listitem>
 586           <para>Is used to inspect OS disk images.</para>
 587           <indexterm zone="ch-system-systemd systemd-dissect">
 588             <primary sortas="b-systemd-dissect">systemd-dissect</primary>
 589           </indexterm>
 590         </listitem>
 591       </varlistentry>
 592
 593       <varlistentry id="systemd-escape">
 594         <term><command>systemd-escape</command></term>
 595         <listitem>
 596           <para>Is used to escape strings for inclusion in systemd unit
 597           names</para>
 598           <indexterm zone="ch-system-systemd systemd-escape">
 599             <primary sortas="b-systemd-escape">systemd-escape</primary>
 600           </indexterm>
 601         </listitem>
 602       </varlistentry>
 603
 604       <varlistentry id="systemd-hwdb">
 605         <term><command>systemd-hwdb</command></term>
 606         <listitem>
 607           <para>Is used to manage the hardware database (hwdb)</para>
 608           <indexterm zone="ch-system-systemd systemd-hwdb">
 609             <primary sortas="b-systemd-hwdb">systemd-hwdb</primary>
 610           </indexterm>
 611         </listitem>
 612       </varlistentry>
 613
 614       <varlistentry id="systemd-id128">
 615         <term><command>systemd-id128</command></term>
 616         <listitem>
 617           <para>Generates and prints id128 strings</para>
 618           <indexterm zone="ch-system-systemd systemd-id128">
 619             <primary sortas="b-systemd-id128">systemd-id128</primary>
 620           </indexterm>
 621         </listitem>
 622       </varlistentry>
 623
 624       <varlistentry id="systemd-inhibit">
 625         <term><command>systemd-inhibit</command></term>
 626         <listitem>
 627           <para>Is used to execute a program with a shutdown, sleep or idle
 628           inhibitor lock taken, preventing an action such as a system shutdown
 629           until the process is completed.</para>
 630           <indexterm zone="ch-system-systemd systemd-inhibit">
 631             <primary sortas="b-systemd-inhibit">systemd-inhibit</primary>
 632           </indexterm>
 633         </listitem>
 634       </varlistentry>
 635
 636       <varlistentry id="systemd-machine-id-setup">
 637         <term><command>systemd-machine-id-setup</command></term>
 638         <listitem>
 639           <para>Is used by system installer tools to initialize the machine ID
 640           stored in <filename>/etc/machine-id</filename> at install time with a
 641           randomly generated ID</para>
 642           <indexterm zone="ch-system-systemd systemd-machine-id-setup">
 643             <primary sortas="b-systemd-machine-id-setup">systemd-machine-id-setup</primary>
 644           </indexterm>
 645         </listitem>
 646       </varlistentry>
 647
 648       <varlistentry id="systemd-mount">
 649         <term><command>systemd-mount</command></term>
 650         <listitem>
 651           <para>Is used to temporarily mount or automount disks.</para>
 652           <indexterm zone="ch-system-systemd systemd-mount">
 653             <primary sortas="b-systemd-mount">systemd-mount</primary>
 654           </indexterm>
 655         </listitem>
 656       </varlistentry>
 657
 658       <varlistentry id="systemd-notify">
 659         <term><command>systemd-notify</command></term>
 660         <listitem>
 661           <para>Is used by daemon scripts to notify the init system about status
 662           changes</para>
 663           <indexterm zone="ch-system-systemd systemd-notify">
 664             <primary sortas="b-systemd-notify">systemd-notify</primary>
 665           </indexterm>
 666         </listitem>
 667       </varlistentry>
 668
 669       <varlistentry id="systemd-nspawn">
 670         <term><command>systemd-nspawn</command></term>
 671         <listitem>
 672           <para>Is used to run a command or OS in a light-weight namespace
 673           container</para>
 674           <indexterm zone="ch-system-systemd systemd-nspawn">
 675             <primary sortas="b-systemd-nspawn">systemd-nspawn</primary>
 676           </indexterm>
 677         </listitem>
 678       </varlistentry>
 679
 680       <varlistentry id="systemd-path">
 681         <term><command>systemd-path</command></term>
 682         <listitem>
 683           <para>Is used to query system and user paths</para>
 684           <indexterm zone="ch-system-systemd systemd-path">
 685             <primary sortas="b-systemd-path">systemd-path</primary>
 686           </indexterm>
 687         </listitem>
 688       </varlistentry>
 689
 690       <varlistentry id="systemd-repart">
 691         <term><command>systemd-repart</command></term>
 692         <listitem>
 693           <para>Is used to grow and add partitions to a partition table when
 694           systemd is used in an OS image (e.g. a container).</para>
 695           <indexterm zone="ch-system-systemd systemd-repart">
 696             <primary sortas="b-systemd-repart">systemd-repart</primary>
 697           </indexterm>
 698         </listitem>
 699       </varlistentry>
 700
 701       <varlistentry id="systemd-resolve">
 702         <term><command>systemd-resolve</command></term>
 703         <listitem>
 704           <para>Is used to resolve domain names, IPV4 and IPv6 addresses, DNS
 705           resource records, and services</para>
 706           <indexterm zone="ch-system-systemd systemd-resolve">
 707             <primary sortas="b-systemd-resolve">systemd-resolve</primary>
 708           </indexterm>
 709         </listitem>
 710       </varlistentry>
 711
 712       <varlistentry id="systemd-run">
 713         <term><command>systemd-run</command></term>
 714         <listitem>
 715           <para>Is used to create and start a transient .service or a .scope
 716           unit and run the specified command in it. This is useful for
 717           validating systemd units.</para>
 718           <indexterm zone="ch-system-systemd systemd-run">
 719             <primary sortas="b-systemd-run">systemd-run</primary>
 720           </indexterm>
 721         </listitem>
 722       </varlistentry>
 723
 724       <varlistentry id="systemd-socket-activate">
 725         <term><command>systemd-socket-activate</command></term>
 726         <listitem>
 727           <para>Is used to listen on socket devices and launch a process upon
 728           a successful connection to the socket.</para>
 729           <indexterm zone="ch-system-systemd systemd-socket-activate">
 730             <primary sortas="b-systemd-socket-activate">systemd-socket-activate</primary>
 731           </indexterm>
 732         </listitem>
 733       </varlistentry>
 734
 735       <varlistentry id="systemd-tmpfiles">
 736         <term><command>systemd-tmpfiles</command></term>
 737         <listitem>
 738           <para>Creates, deletes and cleans up volatile and temporary files and
 739           directories, based on the configuration file format and location
 740           specified in
 741           <filename class="directory">tmpfiles.d</filename> directories</para>
 742           <indexterm zone="ch-system-systemd systemd-tmpfiles">
 743             <primary sortas="b-systemd-tmpfiles">systemd-tmpfiles</primary>
 744           </indexterm>
 745         </listitem>
 746       </varlistentry>
 747
 748       <varlistentry id="systemd-umount">
 749         <term><command>systemd-umount</command></term>
 750         <listitem>
 751           <para>Unmounts mount points</para>
 752           <indexterm zone="ch-system-systemd systemd-umount">
 753             <primary sortas="b-systemd-umount">systemd-umount</primary>
 754           </indexterm>
 755         </listitem>
 756       </varlistentry>
 757
 758       <varlistentry id="systemd-tty-ask-password-agent">
 759         <term><command>systemd-tty-ask-password-agent</command></term>
 760         <listitem>
 761           <para>Is used to list and/or process pending systemd password
 762           requests</para>
 763           <indexterm zone="ch-system-systemd systemd-tty-ask-password-agent">
 764             <primary sortas="b-systemd-tty-ask-password-agent">systemd-tty-ask-password-agent</primary>
 765           </indexterm>
 766         </listitem>
 767       </varlistentry>
 768
 769       <varlistentry id="telinit">
 770         <term><command>telinit</command></term>
 771         <listitem>
 772           <para>Tells <command>init</command> which run-level to change
 773           to</para>
 774           <indexterm zone="ch-system-systemd telinit">
 775             <primary sortas="b-telinit">telinit</primary>
 776           </indexterm>
 777         </listitem>
 778       </varlistentry>
 779
 780       <varlistentry id="timedatectl">
 781         <term><command>timedatectl</command></term>
 782         <listitem>
 783           <para>Is used to query and change the system clock and its settings
 784           </para>
 785           <indexterm zone="ch-system-systemd timedatectl">
 786             <primary sortas="b-timedatectl">timedatectl</primary>
 787           </indexterm>
 788         </listitem>
 789       </varlistentry>
 790
 791       <varlistentry id="udevadm">
 792         <term><command>udevadm</command></term>
 793         <listitem>
 794           <para>Is a generic udev administration tool which controls the udevd
 795           daemon, provides info from the Udev hardware database, monitors
 796           uevents, waits for uevents to finish, tests udev configuration, and
 797           triggers uevents for a given device</para>
 798           <indexterm zone="ch-system-systemd udevadm">
 799             <primary sortas="b-udevadm">udevadm</primary>
 800           </indexterm>
 801         </listitem>
 802       </varlistentry>
 803
 804       <varlistentry id="libsystemd">
 805         <term><filename class="libraryfile">libsystemd</filename></term>
 806         <listitem>
 807           <para>Is the main systemd utility library</para>
 808           <indexterm zone="ch-system-systemd libsystemd">
 809             <primary sortas="c-libsystemd">libsystemd</primary>
 810           </indexterm>
 811         </listitem>
 812       </varlistentry>
 813
 814       <varlistentry id="libudev">
 815         <term><filename class="libraryfile">libudev</filename></term>
 816         <listitem>
 817           <para>Is a library to access Udev device information</para>
 818           <indexterm zone="ch-system-systemd libudev">
 819             <primary sortas="c-libudev">libudev</primary>
 820           </indexterm>
 821         </listitem>
 822       </varlistentry>
 823
 824     </variablelist>
 825
 826   </sect2>
 827
 828 </sect1>