Converting Files under Linux

Convert Images

• Use the powerful command convert

  convert file.jpg file.gif
  convert file.tiff file.jpg
  

  The command convert can convert between several formats and has a lot of options, see man convert

• Resizing an image

  convert -resize 50%       file.jpg file_small.jpg
  convert -resize 200x200   file.jpg file_small.jpg      # ratio will be kept
  convert -resize 1024x768! file.jpg file_desktop.jpg    # ! = force the new size
  

• Rotating an image

  convert -rotate 90 file.jpg file_new.jpg
  

Convert between Windows/Mac and Linux text files

• Use dos2unix and unix2dos

  dos2unix win.txt linux.txt
  mac2unix mac.txt linux.txt
  unix2dos linux.txt win_mac.txt
  

Convert text files between different character encodings

• Use iconv to convert a text file

  iconv --from-code=UTF-8 --to-code=ISO-8859-1 text_in_utf-8.txt > text_in_iso-8859-1.txt
  

Convert PS and EPS Files

There is normally more than one way to convert files. Just try out which tool produces the best results in your case.

• Convert PS to PDF

  ps2pdf file.ps
  ps2pdf -sPAPERSIZE=a4 -dOptimize=true -dEmbedAllFonts=true file.ps
  pstoedit file.ps file.pdf
  

• Convert EPS to PDF

  epstopdf file.eps
  pstoedit file.eps file.pdf
  

• Convert PS to EPS

  ps2eps file.ps
  

• Convert to a "better" PS

  ps2ps   file.ps  new.ps    
  eps2eps file.eps new.eps   
  ps2ps2  file.[ps|eps|pdf] new.ps    # converts to PS level 2
  

• Extract text from PS

  ps2ascii file.ps file.txt
  

• Convert a postscript file to png

  gs -r300 -dNOPAUSE -dUseCropBox -dBATCH -sDEVICE=pngalpha -sOutputFile=file.png file.ps    # r300 = resolution of 300 dpi
  

• Convert a postscript file to jpg

  gs -r300 -dNOPAUSE -dUseCropBox -dBATCH -sDEVICE=jpeg -sOutputFile=file.jpg file.ps    # r300 = resolution of 300 dpi
  

• Convert a transparent eps (in cmyk) to a png file

  convert -colorspace rgb file.eps file.png
  

Convert GRIB into NETCDF files

• Use NCL to convert. First load ncl module

  module load ncl
  

• Rename your GRIB file. The name should have .grb as extension

  mv mygribfile mygribfile.grb
  

• Convert to NETCDF

  ncl_convert2nc mygribfile.grb
  

  The resulting NETCDF file will be mygribfile.nc

• For more information see http://www.ncl.ucar.edu/Document/Tools/ncl_convert2nc.shtml

Convert PDF Files

• Use pdftops to convert PDF to PS

  pdftops file.pdf
  

  Note: pdf2ps does also convert PDF to PS, but normally the result is worse.

• Extract text from PDF

  pdftotext file.pdf
  # or use ps2ascii
  pdftops file.pdf
  ps2ascii file.ps file.txt
  

• Convert a PDF file to images (one image per page)

  pdftoppm file.pdf image
  

  Convert page 2 (-f 2) to page 5 (-l 5) with a resoltion of 300 dpi (-r 300) to five PPM image files

  pdftoppm -f 2 -l 5 -r 300 file.pdf image
  

• Extract images from PDF files

  pdfimages file.pdf image
  pdfimages -j file.pdf image    # write images if possible as JPEG files
  

• Open the PDF File with an application and save it in a different format. Programs that can open PDF files:

  abiword
  oowriter
  

Manipulating PDF Files

• Use pdfedit to edit PDF Files

  pdfedit file.pdf
  

• Joining PDF files

  pdfunite file1.pdf file2.pdf file-new.pdf
  pdfjoin file1.pdf file2.pdf                # alternative
  

• Splitting a PDF file into pages

  qpdf --split-pages file.pdf %d-out.pdf
  

• Extract certain pages from a PDF. For example page 22-36

  qpdf input.pdf --pages . 1-10 -- output.pdf
  pdftops input.pdf - | psselect -p22-36 | ps2pdf - output_p22-p36.pdf
  

• Extract images from PDF files

  pdfimages -j file.pdf image
  

• Rotating PDF file

  pdf90 file.pdf
  

• Put several pages on one page:

  pdfnup --nup 2x1 file.pdf     # 2 pages side by side
  pdfnup --nup 2x2 file.pdf     # 4 pages on one page
  

Convert Matlab EPS Files

• Convert Matlab eps file in a pixel graphic like png, jpg: First convert the eps file into a pdf file. Afterwards convert the pdf file into a png or jpg file

  epstopdf matlab_plot.eps 
  convert -density 100 matlab_plot.pdf matlab_plot.png
  

  • Choose a higher number than 100 to get a higher resolution of the image
  • Instead of png you can convert to matlab_plot.jpg

• Convert Matlab eps file into a .emf file (Enhanced Meta File format). emf is still a vector based format and can be imported by openoffice.

  pstoedit -pta matlab_plot.eps matlab_plot.emf
  

  The crucial option is -pta, which fixes the ugly looking font when you directly import the eps file into openofffice (-pta sets correct inter-letter spacing).
  With the above command the boundary box will be still broken (too large). If you first convert it into a pdf file it will be ok.

  epstopdf matlab_plot.eps
  pstoedit -pta matlab_plot.pdf matlab_plot.emf
  

Convert tar files into zip files

• Windows users may not be able to open tar or tar.gz files. The following commands "convert" these files to zip files

  tar xfv  file.tar    | zip file.zip "-@"
  tar xfvz file.tar.gz | zip file.zip "-@"
  

Convert MS Excel and MS Word files

• Convert xls (Excel) files to csv (comma-separated values) files:

  xls2csv -x file.xls -c file.cvs -a UTF-8
  

• Convert MS Word to plain text:

  abiword --to=txt file.doc
  

• Alternatively open the file with LibreOffice.

Create a Movie out of Images

Programs

• mencoder: Encoding from multiple input image files: http://www.mplayerhq.hu/DOCS/HTML/en/menc-feat-enc-images.html:
• convert: create animated GIFs

Create animated gif with convert

• Animated gif file created from a series of png or gif files ( see also man convert):

  convert -delay 30 -loop 0 *.png animated.gif
  convert -delay 30 -loop 0 *.gif animated.gif
  

mencoder takes jpg or png files as imput. Note: mencoder needs png with 8bit color depth, use option -depth 8

• Convert eps to png files

  mogrify -format png -depth 8 -alpha off -density 600 -resample 150 *.eps
  

• Convert jpg tp png files and keep the quality

  mogrify -format png -depth 8 -quality 100 *.jpg
  

Create movies with mencoder (see also man mencoder)

• Create AVI movie file with MPEG4 codec (fps = frames per second):

  mencoder mf://*.jpg -mf fps=5 -ovc lavc -o output_mpeg4.avi
  mencoder mf://*.png -mf fps=5 -ovc lavc -o output_mpeg4.avi
  

• Create AVI file with XVID codec

  mencoder mf://*.png -mf fps=5 -ovc xvid -xvidencopts fixed_quant=4  -o output_xvid.avi
  

• Create AVI file with X264 codec (use 2 pass mode: pass=1 will analyze the frames, pass=2 will create the movie)

  mencoder mf://*.png -mf fps=5 -o /dev/null       -ovc x264 -x264encopts pass=1:turbo:bitrate=1600:bframes=1:me=umh:partitions=all:trellis=1:qp_step=4:qcomp=0.7:direct_pred=auto:keyint=300
  mencoder mf://*.png -mf fps=5 -o output_x264.avi -ovc x264 -x264encopts pass=2:turbo:bitrate=1600:bframes=1:me=umh:partitions=all:trellis=1:qp_step=4:qcomp=0.7:direct_pred=auto:keyint=300
  

• X264 and XVID codecs create smaller and qualitative better files than MPEG4 codec, where has X264 creates smaller files than XVID.
• Note: For mencoder the file should not be too large. 1000x1000 is still fine

Convert Movie/Animation Files

• Convert MPEG4 movie to Quicktime (qtrle) movie

  ffmpeg -i output_mpeg4.avi -f mov -vcodec qtrle output.mov 
  

• Convert animated GIF into MPEG4 movie. First extract individual pictures out of the animated gif and save them as png files

  convert animation.gif animation%02d.png
  

  Now create out of the png files a MPEG4 movie

  mencoder mf://*.png -mf fps=5 -ovc lavc -o output_mpeg4.avi
  

• Converting Flash movie

  ffmpeg -i myvideo.flv -f avi -vcodec mpeg4 myvideo_mpeg4.avi
  

Convert Audio Files

• Convert WAV to MP3. Set the bit rate with option -b

  lame -b 320 file.wav file.mp3
  

• Convert WAV to OGG. Set quality between -1 (very low) and 10 (very high) with option -q:

  oggenc -q 8 file.wav 
  

• Convert audio files using sox

  sox file.mp3 file.ogg
  sox file.ogg file.mp3
  

• Convert media files using mplayer. Mplayer can convert every file format, which he can play, to .wav

  mplayer -vo null -vc dummy -af resample=44100 -ao pcm:waveheader:file=output.wav input.xxx
  

• Converting a bunch of files using a for loop (works in bash shell only!)

  for f in *.wav;  do lame -b 320 "$f" "${f%.wav}.mp3"; done
  for f in *.flac; do flac -cd "$f" | lame -b 320 - "${f%.flac}.mp3"; done
  for f in *.ogg;  do sox "$f" "${f%.ogg}.mp3"; done
  for f in *.ogg;  do oggdec -o - "$f" | lame -b 256 - "${f%.ogg}.mp3"; done
  for f in *.wma ; do mplayer -vo null -vc dummy -af resample=44100 -ao pcm:waveheader "$f" && lame -b 256 audiodump.wav -o "${f%.wma}.mp3"; done; rm -f audiodump.wav 
  

Extract Audio from a Video File

• Extract MP3 audio from MP4 video

  for f in *.mp4; do ffmpeg -i "$f" -vn -ar 44100 -ac 2 -ab 320k -f mp3 "${f%.mp4}.mp3"; done
  

• Extract MP3 audio from MKV video

  for f in *.mkv; do ffmpeg -i "$f" -vn -ar 44100 -ac 2 -ab 320k -f mp3 "${f%.mkv}.mp3"; done