ghostscript

Convert PDF to images

$ gs -dNOPAUSE -dBATCH -sDEVICE=png16m -r300 -sOutputFile=[page-%d.png] [input.pdf]

$ gs -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=[merged.pdf] [file1.pdf] [file2.pdf]

$ gs -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -dPDFSETTINGS=/ebook -sOutputFile=[small.pdf] [large.pdf]

$ gs -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=[output.pdf] [input.ps]

$ gs -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -dFirstPage=[2] -dLastPage=[5] -sOutputFile=[extract.pdf] [input.pdf]

gs [options] [files]

Ghostscript (gs) is an interpreter for PostScript and PDF. It renders documents to various output formats, converts between formats, and processes print jobs. It is the engine behind many PDF tools and print systems on Unix/Linux.
The tool supports a wide range of output devices for rasterization, format conversion, and print processing. PDF manipulation includes merging, splitting, compressing, and converting between quality levels.

-dNOPAUSE

Don't pause between pages.

Exit after processing.

Output device (pdfwrite, png16m, jpeg, etc.).

Output filename (use %d for page numbers).

Resolution in DPI.

PDF quality: /screen, /ebook, /printer, /prepress.

Start page.

End page.

PDF version (1.4, 1.5, etc.).

/etc/ghostscript/

System-wide configuration directory for font mappings, resource files, and initialization scripts.

User-specific Ghostscript resources and configuration overrides.

Complex command-line syntax. Some operations require specific device drivers. Font handling may need configuration. Security settings restrict file operations.

Ghostscript was started by L. Peter Deutsch in 1988 as a free PostScript interpreter. It's now developed by Artifex Software and remains fundamental to Unix/Linux printing and PDF processing.

pdf2ps(1), ps2pdf(1), pdftk(1), convert(1)