Working with pdfs from the command line
Merge pdfs from Bash
sudo apt install -y pdftk
pdftk file1.pdf file2.pdf cat output mergedfile.pdf
from here
Merge using ghostscript:
gs -q -dBATCH -dNOPAUSE -sDEVICE=pdfwrite -sOutputFile=merged.pdf simple1.pdf simple2.pdf simple3.pdf
from here
Shrink a PDF from the command line
gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/ebook -dNOPAUSE -dQUIET -dBATCH -sOutputFile=output.pdf input.pdf
other compession settings:
/screen: lowest/ebook: medium/printer: high/prepress: very high/default: balanced
Convert to PDF-A
gs -dPDFA -dBATCH -dNOPAUSE -sColorConversionStrategy=UseDeviceIndependentColor -sDEVICE=pdfwrite -dPDFACompatibilityPolicy=2 -sOutputFile="outputfile.pdf" "inputfile.pdf"