[리눅스마스터]제1502회 리눅스마스터 1급 2차 시험 단답식 풀이 1

1. 다음은 사용자 생성 시에 참고하는 설정 파일의 내용이다. ( 괄호 ) 안에 알맞은 내용을 적으시오.

# cat ( ① )
HOME=/home
INACTIVE=-1
EXPIRE=
SHELL=/bin/bash
SKEL=( ② )

<조 건>
- 사용자 생성 시에 참고하는 설정 파일의 절대경로를 적으시오.
- 사용자 생성 시에 제공되는 파일 목록이 들어 있는 디렉터리를 절대경로로 적으시오.

 

/etc/default/useradd : useradd 명령어로 계정 생성 시 기본 값을 지정한 파일

 

[root@server1 ~]# find / -name useradd
/etc/default/useradd

 

[root@server1 ~]# vi /etc/default/useradd

# useradd defaults file
GROUP=100
HOME=/home
INACTIVE=-1
EXPIRE=
SHELL=/bin/bash
SKEL=/etc/skel
CREATE_MAIL_SPOOL=yes

 

① /etc/default/useradd

② /etc/skel

 

2. 다음은 리눅스에서 파일시스템을 검사하는 내용이다. ( 괄호 ) 안에 알맞은 내용을 적으시오.

# umount /dev/sdb1
# fsck ( ① ) ( ② ) ext4 /dev/sdb1

<조 건>
- 검사가 수행될 파티션은 /dev/sdb1 이다.

- 검사할 파티션은 ext4 이며, 실제 검사를 실행하지 않고 수행될 내용을 출력한다.

 

fsck : 리눅스 파일시스템 점검 프로그램

 

[root@server1 ~]# man fsck

OPTIONS
       -l     Lock the whole-disk device by an exclusive flock(2).  This option can be  used  with  one  device
              only  (this  means  that -A and -l are mutually exclusive).  This option is recommended when more
              fsck(8) instances are executed in the same time.  The option is ignored when  used  for  multiple
              devices  or for non-rotating disks.  fsck does not lock underlying devices when executed to check
              stacked devices (e.g. MD or DM) -- this feature is not implemented yet.

       -r     Report certain statistics for each fsck when it completes. These statistics include the exit sta‐
              tus,  the maximum run set size (in kilobytes), the elapsed all-clock time and the user and system
              CPU time used by the fsck run. For example:

              /dev/sda1: status 0, rss 92828, real 4.002804, user 2.677592, sys 0.86186

       -s     Serialize fsck operations.  This is a good idea if you are checking multiple filesystems and  the
              checkers  are  in  an interactive mode.  (Note: e2fsck(8) runs in an interactive mode by default.
              To make e2fsck(8) run in a non-interactive mode, you must either specify the -p or -a option,  if
              you wish for errors to be corrected automatically, or the -n option if you do not.)

       -t fslist
              Specifies  the type(s) of filesystem to be checked.  When the -A flag is specified, only filesys‐
              tems that match fslist are checked.  The fslist parameter is a comma-separated list  of  filesys‐
              tems and options specifiers.  All of the filesystems in this comma-separated list may be prefixed
              by a negation operator 'no' or '!', which requests that only  those  filesystems  not  listed  in
              fslist will be checked.  If none of the filesystems in fslist is prefixed by a negation operator,
              then only those listed filesystems will be checked.

              Options specifiers may be included in the comma-separated fslist.   They  must  have  the  format
              opts=fs-option.   If  an  options  specifier  is present, then only filesystems which contain fs-
              option in their mount options field of /etc/fstab will be checked.  If the options  specifier  is
              prefixed  by a negation operator, then only those filesystems that do not have fs-option in their
              mount options field of /etc/fstab will be checked.

              For example, if opts=ro appears in fslist, then only filesystems listed in /etc/fstab with the ro
              option will be checked.

              For  compatibility  with Mandrake distributions whose boot scripts depend upon an unauthorized UI
              change to the fsck program, if a filesystem type of loop is found in fslist, it is treated as  if
              opts=loop were specified as an argument to the -t option.

              Normally,  the  filesystem  type  is  deduced by searching for filesys in the /etc/fstab file and
              using the corresponding entry.  If the type can not be  deduced,  and  there  is  only  a  single
              filesystem  given  as  an argument to the -t option, fsck will use the specified filesystem type.
              If this type is not available, then the default filesystem type (currently ext2) is used.
               -A     Walk through the /etc/fstab file and try to check all filesystems in one  run.   This  option  is
              typically  used  from  the  /etc/rc  system initialization file, instead of multiple commands for
              checking a single filesystem.

              The root filesystem will be checked first unless the -P option is specified (see  below).   After
              that,  filesystems  will  be checked in the order specified by the fs_passno (the sixth) field in
              the /etc/fstab file.  Filesystems with a fs_passno value of 0 are skipped and are not checked  at
              all.   Filesystems  with  a  fs_passno  value of greater than zero will be checked in order, with
              filesystems with the lowest fs_passno number being checked first.  If there are multiple filesys‐
              tems  with  the  same  pass number, fsck will attempt to check them in parallel, although it will
              avoid running multiple filesystem checks on the same physical disk.

              fsck does not check stacked devices (RAIDs, dm-crypt, ...) in parallel  with  any  other  device.
              See below for FSCK_FORCE_ALL_PARALLEL setting.  The /sys filesystem is used to detemine dependen‐
              cies between devices.

              Hence, a very common configuration in /etc/fstab files is to set the root filesystem  to  have  a
              fs_passno  value of 1 and to set all other filesystems to have a fs_passno value of 2.  This will
              allow fsck to automatically run filesystem checkers in parallel if it is advantageous to  do  so.
              System  administrators  might choose not to use this configuration if they need to avoid multiple
              filesystem checks running in parallel for some reason --- for example, if the machine in question
              is short on memory so that excessive paging is a concern.

              fsck  normally does not check whether the device actually exists before calling a filesystem spe‐
              cific checker.  Therefore non-existing devices may cause the system to  enter  filesystem  repair
              mode  during boot if the filesystem specific checker returns a fatal error.  The /etc/fstab mount
              option nofail may be used to have fsck skip non-existing devices.  fsck also  skips  non-existing
              devices that have the special filesystem type auto.

       -C [fd]
              Display completion/progress bars for those filesystem checkers (currently only for ext2 and ext3)
              which support them.  fsck will manage the filesystem checkers so that only one of them will  dis‐
              play  a  progress  bar at a time.  GUI front-ends may specify a file descriptor fd, in which case
              the progress bar information will be sent to that file descriptor.

       -M     Do not check mounted filesystems and return an exit code of 0 for mounted filesystems.

       -N     Don't execute, just show what would be done.

       -P     When the -A flag is set, check the root filesystem in parallel with the other filesystems.   This
              is  not the safest thing in the world to do, since if the root filesystem is in doubt things like
              the e2fsck(8) executable might be corrupted!  This option is mainly provided for those  sysadmins
              who  don't  want  to repartition the root filesystem to be small and compact (which is really the
              right solution).

       -R     When checking all filesystems with the -A flag, skip the root filesystem.   (This  is  useful  in
              case the root filesystem has already been mounted read-write.)

       -T     Don't show the title on startup.

       -V     Produce verbose output, including all filesystem-specific commands that are executed.

 

<주요 옵션>

-t : 점검할 파일 시스템 타입 지정

-N : 실행하지는 않고 어떤 작업을 할 것인지 출력

-T : 시작할 때 버전을 출력하지 않음

-R : -A 옵션과 같이 사용시 읽기 / 쓰기로 마운팅 되어 있는 루트 파일 시스템은 제외

-A : /etc/fstab 파일에 기록된 모든 파일시스템을 점검

 

① -N

② -t

 

3. 사용자 시스템에 로그인하여 프로그램을 실행시킨 후 발생되는 HUP(Hangup) 시그널을 무시하고 해당 프로그램이 

지속적으로 실행 되도록 하고자 한다. ( 괄호 ) 안에 알맞은 내용을 적으시오.

# ( ① ) tar cvf home.tar /home ( ② )

 

[root@server1 ~]# man nohup

NAME
       nohup - run a command immune to hangups, with output to a non-tty

SYNOPSIS
       nohup COMMAND [ARG]...
       nohup OPTION

DESCRIPTION
       Run COMMAND, ignoring hangup signals.

       --help display this help and exit

       --version
              output version information and exit

       If  standard  input is a terminal, redirect it from /dev/null.  If standard output is a terminal, append
       output to 'nohup.out' if possible, '$HOME/nohup.out' otherwise.  If standard error is a terminal,  redi‐
       rect it to standard output.  To save output to FILE, use 'nohup COMMAND > FILE'.

       NOTE: your shell may have its own version of nohup, which usually supersedes the version described here.
       Please refer to your shell's documentation for details about the options it supports.

       GNU coreutils online help: <http://www.gnu.org/software/coreutils/> Report  nohup  translation  bugs  to
       <http://translationproject.org/team/>

AUTHOR
       Written by Jim Meyering.

COPYRIGHT
       Copyright  ©  2013  Free  Software  Foundation,  Inc.   License  GPLv3+:  GNU  GPL  version  3  or later
       <http://gnu.org/licenses/gpl.html>.
       This is free software: you are free to change and redistribute it.  There is NO WARRANTY, to the  extent
       permitted by law.

SEE ALSO
       The  full documentation for nohup is maintained as a Texinfo manual.  If the info and nohup programs are
       properly installed at your site, the command

              info coreutils 'nohup invocation'

       should give you access to the complete manual.

 

nohup : 리눅스에서 프로세스를 실행한 터미널의 세션 연결이 끊어지더라도 지속적으로 동작 할 수 있게 해주는 명령어

＆ : 백그라운드로 해당 명령 실행

 

① nohup

② &