2014/05/19

Linux 不用超級使用者的掛載(mount)方式(The non-superuser mounts.)

Linux 不用超級使用者的掛載(mount)方式(The non-superuser mounts.)
正常再 LINUX 內只有超級使用者可以掛載檔案系統,如果要讓一般使用者掛載某個檔案,只需要再 fstab 的參數加入 user 這個選項一般使用者就可以使用一般使用者的權限掛載檔案系統。


mtchang@mtchang-BM6660-BM6360:~$ cat /etc/fstab
# /etc/fstab: static file system information.
# that works even if disks are added and removed. See fstab(5).
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
UUID=9c55a017-2ecc-46f2-853c-c43215884821 /home/mtchang/3gbhd        ext4    defaults,user    0    0

詳細請見 man 5 fstab

      The fourth field (fs_mntops).
              This field describes the mount options associated with the filesystem.

              It  is  formatted as a comma separated list of options.  It contains at least the type of mount
              plus any additional options appropriate to the filesystem type. For documentation on the avail‐
              able  mount  options,  see  mount(8).   For  documentation  on  the available swap options, see
              swapon(8).

              Basic file system independent options are:

              defaults
                     use default options: rw, suid, dev, exec, auto, nouser, and async.

              noauto do not mount when "mount -a" is given (e.g., at boot time)

              user   allow a user to mount

              owner  allow device owner to mount

              comment
                     for use by fstab-maintaining programs

              nofail do not report errors for this device if it does not exist.

什樣的狀況會用到這個方式勒?我的狀況是用在個人桌面使用的 linux 系統,因為大容量的硬碟是自己再備份資料時才會用到存取,且因為買的較便宜的速度相對較慢。所以就把他拿來掛載在個人工作的目錄上面,所以使用到這樣的方式。至於主系統碟,當然能用 SSD 之類的就更棒了,但畢竟 SSD 還是太貴呀!!!



2014/05/09

linux 文字命令列的 youtube-dl


WALALA.....為何有這個指令被收錄在 ubuntu 和 rhel EPEL 的套件內勒!!!

安裝 youtube-dl 工具

mtchang@ ~$ sudo apt-get install youtube-dl
[sudo] password for mtchang:
Reading package lists... Done
Building dependency tree      
Reading state information... Done
The following extra packages will be installed:
  libav-tools libavdevice53 libavfilter3 libbs2b0 libgif4 libquvi-scripts libquvi7 libvdpau1
  mplayer2 rtmpdump
Suggested packages:
  frei0r-plugins nvidia-vdpau-driver vdpau-driver ffmpeg mplayer
The following NEW packages will be installed:
  libav-tools libavdevice53 libavfilter3 libbs2b0 libgif4 libquvi-scripts libquvi7 libvdpau1
  mplayer2 rtmpdump youtube-dl
0 upgraded, 11 newly installed, 0 to remove and 36 not upgraded.
Need to get 4,766 kB of archives.
After this operation, 14.3 MB of additional disk space will be used.
Do you want to continue? [Y/n] y

執行擷取某個影音檔
mtchang@~/Videos$ youtube-dl http://www.youtube.com/watch?v=iV8JDbtXZm4
[youtube] Setting language
[youtube] iV8JDbtXZm4: Downloading webpage
[youtube] iV8JDbtXZm4: Downloading video info webpage
[youtube] iV8JDbtXZm4: Extracting video information
[download] Destination: 〈島嶼天光〉(Island's Sunrise)藝術計劃 太陽花學運歌曲-iV8JDbtXZm4.mp4
[download] 100% of 81.57MiB in 00:09


裡面有個功能是可以將抓下來的影片直接透過後製的轉換程式直接轉換成為 mp3

   Post-processing Options:
              -x, --extract-audio              convert video files to audio-only files
                                               (requires ffmpeg or avconv and ffprobe or
                                               avprobe)
              --audio-format FORMAT            "best", "aac", "vorbis", "mp3", "m4a",
                                               "opus", or "wav"; best by default
              --audio-quality QUALITY          ffmpeg/avconv audio quality specification,
                                               insert a value between 0 (better) and 9
                                               (worse) for VBR or a specific bitrate like
                                               128K (default 5)
              --recode-video FORMAT            Encode the video to another format if
                                               necessary (currently supported:
                                               mp4|flv|ogg|webm)
              -k, --keep-video                 keeps the video file on disk after the
                                               post-processing; the video is erased by
                                               default
              --no-post-overwrites             do not overwrite post-processed files; the
                                               post-processed files are overwritten by
                                               default
              --embed-subs                     embed subtitles in the video (only for mp4
                                               videos)
              --add-metadata                   write metadata to the video file
              --xattrs                         write metadata to the video file's xattrs
                                               (using dublin core and xdg standards)
              --prefer-avconv                  Prefer avconv over ffmpeg for running the
                                               postprocessors (default)
              --prefer-ffmpeg                  Prefer ffmpeg over avconv for running the
                                               postprocessors




作者的網站:http://rg3.github.io/youtube-dl/

詳細的文件請參考這裡:http://rg3.github.io/youtube-dl/documentation.html#d1

2014/05/04

某個 54 運動 ?? 的所佔面積

今天某個 54 運動 ?? 的所佔面積計算,剛剛用 google map 和 autocad 小算了一下,看起來照片中的區塊為 3751 平方公尺,至於每平方公尺要乘以多少人.,請大家參考底下的圖片心算一下巴。









延伸閱讀:
http://newtalk.tw/news/2014/05/04/46931.html  凱道「新五四運動」 警方估有萬人參與

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