wisdomsoar-blog

[wisdomsoar-blog]

GNU/Linux most wanted

How can I find the version of Ubuntu that is installed? lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description:    Ubuntu 16.10 Release:        16.10 Codename:       yakkety

ref: GNU/Linux most wanted

Handling files and directories Changing directories: cd ~bill (home directory of user bill) Copy files to a directory: cp file1 file2 dir

Copy directories recursively: cp -r source_dir/ dest_dir/ rsync -a source_dir/ dest_dir/ rsync -av --exclude='path/to/exclude' source_dir/ dest_dir

Create a symbolic link: ln -s linked_file link ln -sf linked_file link s: make symbolic links instead of hard links f: remove existing destination files

Rename a file, link or directory: mv source_file dest_file mv -T /path/src /path/dst -T: treate DESTINATION (/path/dst) as a normal file

Remove non-empty directories: rm -rf dir

Remove non-empty directories Recursively: rm -rf `find . -name .git`

Listing files ls l: long listing a: list all files (including hidden files) t: by time (most recent files first) s: by size (biggest files first) r: reverse sort order

List link file recursively: ls -alR | grep "/home/chhuang/500G" -B10 R: recursive

grep B NUM: --before-context=NUM o: only matching 只取出找到的pattern片段 例 dmesg | grep -o 'scsi.*Direct-Access.*ADATA'

awk 以空白做分隔，並列印指定的第幾欄 (從1開始) 例：以空白做分隔，印出第2欄 dmesg | grep -o 'scsi.*Direct-Access.*ADATA' | awk '{print $2}'

How to grep for contents after pattern? https://stackoverflow.com/questions/10358547/how-to-grep-for-contents-after-pattern 取冒號之後的文字：

grep 'potato:' file.txt | sed 's/^.*: //' or

grep 'potato:' file.txt | cut -d\   -f2 or

grep 'potato:' file.txt | awk '{print $2}'

example: Long list with most recent files last: ls -ltr

Displaying file contents Display the first 10 lines of a file: head -10 file

Display the last lines of a file: tail -10 file

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Looking for files Find *log* files in current (.) directory recursively find . -name "*log*"

Find all the .pdf files in current (.) directory recursively and run a command on each find . -name "*.pdf" -exec xpdf {} ';'

對每個找到的檔案執行xxx.sh find . -type f | xargs -n | xxx.sh

在當前目錄遞迴找某關鍵字，並忽略find和grep警告訊息 find . -type f 2>/dev/null | xargs  grep -H  keyword_to_find 2>/dev/null > find_result.txt

在當前目錄找某關鍵字 grep -Ire keryword_to_find l: Do not list binary files (--binary-files=without-match) R: Recursively. Follow all symbolic links. -e PATTERN

尋找linked files (並看完整路徑) find . -type l -ls | grep mnt

locate "*pub*"

copy: https://stackoverflow.com/questions/5410757/delete-lines-in-a-text-file-that-contain-a-specific-string Remove the line and print the output to standard out: sed '/pattern to match/d' ./infile

Remove lines with specified pattern directly from the file: sed -i '/pattern to match/d' ./infile

Archiving Create a compressed archive (TApe ARchive): tar jcvf archive.tar.bz2 dir

tar xvf archive.tar.[gz|bz2|lzma|xz] tar jxvf archive.tar.bz2

tar jxvf archive.bz2

c: create t: test x: extract j: on the fly bzip2 (un)compression

tar xvf archive.tar -C /path/to/directory

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File and partition sizes Show the total size on disk of files or directories (Disk Usage): du -sh dir1 dir2 file1 file2 -s: summarize -h: human

Number of bytes, words and lines in file: wc file (Word Count)

Show the size, total space and free space of the current partition: df -h .

Display these info for all partitions: df -h

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mount samba in Linux (/etc/fstab)

sudo vi /etc/fstab

//172.16.70.151/your_name /path/to/your/local/directory/ cifs rw,username=your_name,password=your_password,uid=your_uid,gid=your_gid,iocharset=utf8,file_mode=0777,dir_mode=0777,noperm 0 0

Make zip file zip -0r bootanimation.zip desc.txt part0 part1 0: not use any compression r: recursively

start to use screen $ screen And press [space] key to skip the spash list screen(s) you used $ screen -ls There are screens on: 19668.pts-14.Aspire-M7720-build-machine (11/21/2017 05:35:28 PM) (Detached) 2345.pts-19.Aspire-M7720-build-machine (11/17/2017 10:44:58 AM) (Detached) delete a specified screen format: screen -X -S [session id] quit example: $ screen -X -S 2345 quit re-attach a screen $ screen -r or format: screen -r [session id] $ screen -r 19668

force attach to a specified session screen -d -r 19668

for loop END=5 for i in $(seq 1 $END); do    echo $i; done

make sequence numbers: for i in {1..4}; do printf "hello '%s'\n" input.mp4 >> list.txt; done

$ for i in {01..05}; do echo "$i"; done 01 02 03 04 05

$ foo=$(printf "%02d" 5) $ echo "${foo}" 05

multimedia: ffmpeg

make mp4 video from bmp files ffmpeg -framerate 60 -i img%03d.bmp -c:v libx264 -pix_fmt yuv420p -crf 0 output_60f.mp4 -crf 0: to create a lossless video

Repeat/loop Input Video with ffmpeg: copy: https://video.stackexchange.com/questions/12905/repeat-loop-input-video-with-ffmpeg This allows you to loop an input without needing to re-encode.

1. Make a text file. Contents of an example text file to repeat 4 times.

file 'input.mp4' file 'input.mp4' file 'input.mp4' file 'input.mp4' Then run ffmpeg:

2. ffmpeg -f concat -i list.txt -c copy output.mp4

dd /data/local/bin/dd 'if=/data/local/tmp/rnd_64M.img' 'of=/mnt/user/rnd_64M.img' 'bs=1024k' 'count=64' 'iflag=fullblock'

/data/local/bin/dd 'if=/mnt/sdc2_mmc/rnd_64M.img' 'of=/mnt/user/rnd.img_64M' 'bs=1024k' 'count=64' 'iflag=direct'

https://community.mellanox.com/s/article/how-to-set-cpu-scaling-governor-to-max-performance--scaling-governor-x

Performance CPU echo performance > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor echo performance > /sys/devices/system/cpu/cpu1/cpufreq/scaling_governor echo performance > /sys/devices/system/cpu/cpu2/cpufreq/scaling_governor echo performance > /sys/devices/system/cpu/cpu3/cpufreq/scaling_governor echo performance > /sys/devices/system/cpu/cpu4/cpufreq/scaling_governor echo performance > /sys/devices/system/cpu/cpu5/cpufreq/scaling_governor echo performance > /sys/devices/system/cpu/cpu6/cpufreq/scaling_governor echo performance > /sys/devices/system/cpu/cpu7/cpufreq/scaling_governor

# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq

3300000

# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq

1200000

# cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq

3210156