1 Tricks and Hacks

Create QR Code:

qrencode -s 15 -d 700 -o labWebsite.png "https://onkyo.u-aizu.ac.jp/#/"

Download videos from Terminal:

yt-dlp 'url'
yt-dlp --extract-audio 'url'

Specs of a Ubuntu system

sc
lshw | less

Beamer presentation with second screen and timer:

 python3 -m pympress pdf_file

Finding creation/access/modify and change date of a file

 stat -x foo

Finding metadata of a file

mdls

Change the contents of a column in a list of files within the same directory (in this case, 5th column ‘z’ by ‘m’)

for f in *; do
awk -v OFS='\t' -F"\t" '{gsub("z","x",$5)}1' $f > 'o'$f
mv 'o'$f $f
awk -v OFS='\t' -F"\t" '{gsub("m","z",$5)}1' $f > 'o'$f
mv 'o'$f $f
awk -v OFS='\t' -F"\t" '{gsub("x","m",$5)}1' $f > 'o'$f
mv 'o'$f $f
done

Extract text from all powerpoint files using Terminal in MacOS

Move to the directory where the pptx files are and run this:

mkdir unzipped 
rm bla.txt
for f in session*.pptx; 
do
rm -r unzipped; 
mkdir unzipped 
unzip "$f" -d unzipped;
grep -hoe "<a:t>[/%&–\'\".()-: 1-9A-Za-z]*</a:t>" unzipped/ppt/slides/slide*.xml| sed 's/<a:t>//g'| sed 's/<\/a:t>//g' >>bla.txt;
done

tar zip a file:

tar -zcvf output.tar.gz path_to_directory/

Find a string within a file in a directory:

 grep -ril "string" dir

Rename files:

for f in *; do      ext="";      [[ $f =~ \. ]] && ext="."${f#*.};      mv "$f" "${f%%.*}"_NO$ext;  done

or

ls -1 *_bla_* | awk -F"_" -v old="bla" -v new="newBla" '$2==old{print "mv "$0 " "$1"_"new"_"$3}' | sh

Move inner files to outer directory

find . -maxdepth 2 -type f -exec mv {} .. \;

copy files in a list (in a textile) from the same directory to a directory

 cat file.csv | xargs -I % cp % PATH_TO_OTHER_DIR

replace a word in all files within a directory

sed -i '.old' 's/phonation/vowels/g' *.textgrid

delete part of the name of a file:

for file in *_auto.TextGrid ; do mv "$file" "${file%_auto.TextGrid}.TextGrid" ; done

Delete the first n characters of a filename

for f in *; do mv "$f" "${f#??}"; done

Add extensions to files in a directory

find . -type f -exec mv '{}' '{}'.wav \;

change the extension of a list of files

for file in *.textgrid; do mv "$file" "${file%.textgrid}.TextGrid"; done

Copy files with the same name but different extension from a folder to a subfolder:

for f in ./DuanStimuliForSubjectiveExperiment/*; 
do 
cp `basename ${f%.*}.TextGrid` ./DuanStimuliForSubjectiveExperiment/;
done

Change the encoding of a set of files

for f in ./*; 
do 
iconv -f SHIFT-JIS -t UTF-8 $f > ./UTF8/$f
done

Convert PDF files to PS

for f in *.pdf; do gs -sDEVICE=ps2write -dNOPAUSE -dBATCH -sOutputFile=./psFigures/$f.ps $f;  done

Convert a batch of PDFs into jpegs

for i in *.pdf; do gs -dQUIET -dBATCH -dNOPAUSE -sDEVICE=jpeg -r144 -sOutputFile=./converted/$(basename $i .pdf).jpg $i; done

Trim the white space around a graphic

for i in *.jpg; do convert $i -trim $i; done

select N random lines from a file:

brew install coreutils
gsort -R input | head -n 100 >output

Merge and compress PDFs in a directory:

gs -dBATCH -dNOPAUSE -q -sDEVICE=pdfwrite -dPDFSETTINGS=/prepress -sPAPERSIZE=a4 -dFIXEDMEDIA -dPDFFitPage -sOutputFile=out.pdf *.pdf

Make a smaller file:

gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dNOPAUSE -dQUIET -dBATCH -sOutputFile=compressed.pdf input.pdf

Make the pdf even smaller at 150 DPI:

gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dNOPAUSE -dQUIET -dBATCH -dPDFSETTINGS=/ebook -sOutputFile=compressed.pdf  input.pdf

Add something to the path:

echo $PATH
export PATH=$PATH:/usr/local/include/faust 

Tricks with Sox

Normalize audio files:

for i in *.wav; do /Applications/sox/sox --norm=-.1 $i ./normalized/$i ; done

for i in *.wav; do /Applications/sox/sox $i equalLengthRecordings/$i trim 0 0.5275; done

for i in *.wav; do /Applications/sox/sox 
$i ~/Desktop/$i fade 0 0.5275 0.01; done

for i in *.wav; do /Applications/sox/soxi -s $i; done
for i in *.wav; do /Applications/sox/sox $i ~/Desktop/$i rate 44100; done

Tricks with ffmpeg

for j in *.m4a; do /Applications/ffmpeg -i "$j" -acodec libmp3lame -ab 320k ../mp3/"$j".mp3 ; done
for file in *.m4a.mp3 ; do mv "$file" "${file%.m4a.mp3}.mp3" ; done

Search LaTeX Documentation:

texdoc library_name

Find the bounding box of a ps/pdf

gs -sDEVICE=bbox -dNOPAUSE -dBATCH  file

Reset the key for SSH connections when the key has changed:

ssh-keygen -R <host>

$ scp foobar.txt your_username@remotehost.edu:/some/remote/directory

copy from remote

scp userbounding@server:/path/to/remotefile.zip /Local/Target/Destination

rsync -avW  -e ssh user@server:/PATH/

scp file user@linsv.u-aizu.ac.jp:/PATH/

https://streamsv.u-aizu.ac.jp/PATH/file

Replacement for finger:

pinky -l

 python3 -m venv path/to/venv
    source path/to/venv/bin/activate
    python3 -m pip install xyz

space in disk:

sudo df -h

sapply(seq(1, length(numbers), by = 2), function(i) { paste(numbers[i], numbers[i + 1], sep = ".")

debug Python MacVIM

import pdb
...
pdb.set_trace()

1   Execute the next statement… with “n” (next)
2   Repeating the last debugging command... with ENTER
3   Quitting it all... with “q” (quit)
4   Printing the value of variables… with “p” (print)
    a) p a
5   Turning off the (Pdb) prompt… with “c” (continue)
6   Seeing where you are… with “l” (list)
7   Stepping into subroutines... with “s” (step into)
8   Continuing... but just to the end of the current subroutine... with “r” (return)
9   Assign a new value
    a) !b = "B"
10  Set a breakpoint
    a) break linenumber
    b) break functionname
    c) break filename:linenumber
11  Temporary breakpoint
    a) tbreak linenumber
12  Conditional breakpoint
    a) break linenumber, condition