Just Setup

사용법: df [<옵션>]... [<파일>]...
Show information about the file system on which each FILE resides,
or all file systems by default.

Mandatory arguments to long options are mandatory for short options too.
-a, --all include pseudo, duplicate, inaccessible file systems
-B, --block-size=SIZE scale sizes by SIZE before printing them; e.g.,

-h, --human-readable print sizes in powers of 1024 (e.g., 1023M)
-H, --si print sizes in powers of 1000 (e.g., 1.1G)
-i, --inodes 블록 사용 대신 inode 정보를 목록화
-k --block-size=1K 와 같음
-l, --local 로컬 파일 시스템만 목록화
-P, --portability use the POSIX output format
-t, --type=TYPE limit listing to file systems of type TYPE
-T, --print-type print file system type
-x, --exclude-type=TYPE limit listing to file systems not of type TYPE
-v (ignored)

Display values are in units of the first available SIZE from --block-size,
and the DF_BLOCK_SIZE, BLOCK_SIZE and BLOCKSIZE environment variables.
Otherwise, units default to 1024 bytes (or 512 if POSIXLY_CORRECT is set).

The SIZE argument is an integer and optional unit (example: 10K is 10*1024).
Units are K,M,G,T,P,E,Z,Y (powers of 1024) or KB,MB,... (powers of 1000).

FIELD_LIST is a comma-separated list of columns to be included. Valid
field names are: 'source', 'fstype', 'itotal', 'iused', 'iavail', 'ipcent',
'size', 'used', 'avail', 'pcent', 'file' and 'target' (see info page).

사용법: cat [<옵션>]... [<파일>]...
Concatenate FILE(s) to standard output.

<파일>이 주어지지 않거나 - 이면 표준 입력을 읽습니다.

-A, --show-all equivalent to -vET
-b, --number-nonblank number nonempty output lines, overrides -n
-e equivalent to -vE
-E, --show-ends display $ at end of each line
-n, --number number all output lines
-s, --squeeze-blank suppress repeated empty output lines
-t -vT와 같음
-T, --show-tabs 탭 문자를 ^I로 표시합니다
-u (무시됨)
-v, --show-nonprinting ^ 와 M- 표기법을 사용합니다 (LFD와 TAB 제외)

예제:
cat f - g f 내용, 표준 입력, g 내용을 순서대로 출력.
cat 표준 입력을 표준 출력으로 복사.

GNU coreutils online help: <http://www.gnu.org/software/coreutils/>
Report cat translation bugs to <http://translationproject.org/team/>
Full documentation at: <http://www.gnu.org/software/coreutils/cat>
or available locally via: info '(coreutils) cat invocation'

Usage: chsh [options] [LOGIN]

Options:
-h, --help display this help message and exit
-R, --root CHROOT_DIR directory to chroot into
-s, --shell SHELL new login shell for the user account