Linux常用命令使用格式

Posted 2020-12-13 qianyuezhan

仅以博客形式记录linux所学，不足之处继续优化

linux系统的常用命令格式基本上是以　　cmd(command) 选项 参数　　的形式书写

例如screen、date、ifconfig等命令

 1 Usage: date [OPTION]... [+FORMAT]
 2   or:  date [-u|--utc|--universal] [MMDDhhmm[[CC]YY][.ss]]
 3 Display the current time in the given FORMAT, or set the system date.
 4 
 5 Mandatory arguments to long options are mandatory for short options too.
 6   -d, --date=STRING         display time described by STRING, not ‘now‘
 7   -f, --file=DATEFILE       like --date once for each line of DATEFILE
 8   -I[TIMESPEC], --iso-8601[=TIMESPEC]  output date/time in ISO 8601 format.
 9                             TIMESPEC=‘date‘ for date only (the default),
10                             ‘hours‘, ‘minutes‘, ‘seconds‘, or ‘ns‘ for date
11                             and time to the indicated precision.
12   -r, --reference=FILE      display the last modification time of FILE
13   -R, --rfc-2822            output date and time in RFC 2822 format.
14                             Example: Mon, 07 Aug 2006 12:34:56 -0600
15       --rfc-3339=TIMESPEC   output date and time in RFC 3339 format.
16                             TIMESPEC=‘date‘, ‘seconds‘, or ‘ns‘ for
17                             date and time to the indicated precision.
18                             Date and time components are separated by
19                             a single space: 2006-08-07 12:34:56-06:00
20   -s, --set=STRING          set time described by STRING
21   -u, --utc, --universal    print or set Coordinated Universal Time (UTC)
22       --help     display this help and exit
23       --version  output version information and exit
24 
25 FORMAT controls the output.  Interpreted sequences are:
26 
27   %%   a literal %
28   %a   locale‘s abbreviated weekday name (e.g., Sun)
29   %A   locale‘s full weekday name (e.g., Sunday)
30   %b   locale‘s abbreviated month name (e.g., Jan)
31   %B   locale‘s full month name (e.g., January)
32   %c   locale‘s date and time (e.g., Thu Mar  3 23:05:25 2005)
33   %C   century; like %Y, except omit last two digits (e.g., 20)
34   %d   day of month (e.g., 01)
35   %D   date; same as %m/%d/%y
36   %e   day of month, space padded; same as %_d
37   %F   full date; same as %Y-%m-%d
38   %g   last two digits of year of ISO week number (see %G)
39   %G   year of ISO week number (see %V); normally useful only with %V
40   %h   same as %b
41   %H   hour (00..23)
42   %I   hour (01..12)
43   %j   day of year (001..366)
44   %k   hour, space padded ( 0..23); same as %_H
45   %l   hour, space padded ( 1..12); same as %_I
46   %m   month (01..12)
47   %M   minute (00..59)
48   %n   a newline
49   %N   nanoseconds (000000000..999999999)
50   %p   locale‘s equivalent of either AM or PM; blank if not known
51   %P   like %p, but lower case
52   %r   locale‘s 12-hour clock time (e.g., 11:11:04 PM)
53   %R   24-hour hour and minute; same as %H:%M
54   %s   seconds since 1970-01-01 00:00:00 UTC
55   %S   second (00..60)
56   %t   a tab
57   %T   time; same as %H:%M:%S
58   %u   day of week (1..7); 1 is Monday
59   %U   week number of year, with Sunday as first day of week (00..53)
60   %V   ISO week number, with Monday as first day of week (01..53)
61   %w   day of week (0..6); 0 is Sunday
62   %W   week number of year, with Monday as first day of week (00..53)
63   %x   locale‘s date representation (e.g., 12/31/99)
64   %X   locale‘s time representation (e.g., 23:13:48)
65   %y   last two digits of year (00..99)
66   %Y   year
67   %z   +hhmm numeric time zone (e.g., -0400)
68   %:z  +hh:mm numeric time zone (e.g., -04:00)
69   %::z  +hh:mm:ss numeric time zone (e.g., -04:00:00)
70   %:::z  numeric time zone with : to necessary precision (e.g., -04, +05:30)
71   %Z   alphabetic time zone abbreviation (e.g., EDT)
72 
73 By default, date pads numeric fields with zeroes.
74 The following optional flags may follow ‘%‘:
75 
76   -  (hyphen) do not pad the field
77   _  (underscore) pad with spaces
78   0  (zero) pad with zeros
79   ^  use upper case if possible
80   #  use opposite case if possible
81 
82 After any flags comes an optional field width, as a decimal number;
83 then an optional modifier, which is either
84 E to use the locale‘s alternate representations if available, or
85 O to use the locale‘s alternate numeric symbols if available.
86 
87 Examples:
88 Convert seconds since the epoch (1970-01-01 UTC) to a date
89   $ date --date=‘@2147483647‘
90 
91 Show the time on the west coast of the US (use tzselect(1) to find TZ)
92   $ TZ=‘America/Los_Angeles‘ date
93 
94 Show the local time for 9AM next Friday on the west coast of the US
95   $ date --date=‘TZ="America/Los_Angeles" 09:00 next Fri‘
96 
97 GNU coreutils online help: <http://www.gnu.org/software/coreutils/>
98 For complete documentation, run: info coreutils ‘date invocation‘

利用date来设置时间

date -s "20200807 12:00:00"

 1 Use: screen [-opts] [cmd [args]]
 2  or: screen -r [host.tty]
 3 
 4 Options:
 5 -4            Resolve hostnames only to IPv4 addresses.
 6 -6            Resolve hostnames only to IPv6 addresses.
 7 -a            Force all capabilities into each window‘s termcap.
 8 -A -[r|R]     Adapt all windows to the new display width & height.
 9 -c file       Read configuration file instead of ‘.screenrc‘.
10 -d (-r)       Detach the elsewhere running screen (and reattach here).
11 -dmS name     Start as daemon: Screen session in detached mode.
12 -D (-r)       Detach and logout remote (and reattach here).
13 -D -RR        Do whatever is needed to get a screen session.
14 -e xy         Change command characters.
15 -f            Flow control on, -fn = off, -fa = auto.
16 -h lines      Set the size of the scrollback history buffer.
17 -i            Interrupt output sooner when flow control is on.
18 -l            Login mode on (update /var/run/utmp), -ln = off.
19 -ls [match]   or
20 -list         Do nothing, just list our SockDir [on possible matches].
21 -L            Turn on output logging.
22 -m            ignore $STY variable, do create a new screen session.
23 -O            Choose optimal output rather than exact vt100 emulation.
24 -p window     Preselect the named window if it exists.
25 -q            Quiet startup. Exits with non-zero return code if unsuccessful.
26 -Q            Commands will send the response to the stdout of the querying process.
27 -r [session]  Reattach to a detached screen process.
28 -R            Reattach if possible, otherwise start a new session.
29 -s shell      Shell to execute rather than $SHELL.
30 -S sockname   Name this session <pid>.sockname instead of <pid>.<tty>.<host>.
31 -t title      Set title. (window‘s name).
32 -T term       Use term as $TERM for windows, rather than "screen".
33 -U            Tell screen to use UTF-8 encoding.
34 -v            Print "Screen version 4.01.00devel (GNU) 2-May-06".
35 -wipe [match] Do nothing, just clean up SockDir [on possible matches].
36 -x            Attach to a not detached screen. (Multi display mode).
37 -X            Execute <cmd> as a screen command in the specified session.

 

在linux使用过程中，如果有人想请你帮忙，可以使用screen程序来操作，使你和被帮助人的终端设备同步打印相同的信息，相当于终端共享，便于解决问题。

screen -S help　　开启一个名为help的screen的页面

screen -ls　　　　查看当前是否有人建立screen页面

screen -x help　　通过help名来加入screen。

加入之后便可以两个终端同步打印输入输出的信息。