In /usr/bin/ps2epsi line 9:
LIBDIR=`dirname $0`
       ^----------^ SC2006: Use $(...) notation instead of legacy backticked `...`.
                ^-- SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
LIBDIR=$(dirname "$0")


In /usr/bin/ps2epsi line 23:
if [ $# -lt 1 -o $# -gt 2 ]; then
              ^-- SC2166: Prefer [ p ] || [ q ] as [ p -o q ] is not well defined.


In /usr/bin/ps2epsi line 24:
	echo "Usage: `basename \"$0\"` file.ps [file.epsi]" 1>&2
                     ^---------------^ SC2006: Use $(...) notation instead of legacy backticked `...`.

Did you mean: 
	echo "Usage: $(basename \"$0\") file.ps [file.epsi]" 1>&2


In /usr/bin/ps2epsi line 32:
	  *.ps)		base=`basename "${infile}" .ps` ;;
                             ^------------------------^ SC2006: Use $(...) notation instead of legacy backticked `...`.

Did you mean: 
	  *.ps)		base=$(basename "${infile}" .ps) ;;


In /usr/bin/ps2epsi line 33:
	  *.cps)	base=`basename "${infile}" .cps` ;;
                             ^-------------------------^ SC2006: Use $(...) notation instead of legacy backticked `...`.

Did you mean: 
	  *.cps)	base=$(basename "${infile}" .cps) ;;


In /usr/bin/ps2epsi line 34:
	  *.eps)	base=`basename "${infile}" .eps` ;;
                             ^-------------------------^ SC2006: Use $(...) notation instead of legacy backticked `...`.

Did you mean: 
	  *.eps)	base=$(basename "${infile}" .eps) ;;


In /usr/bin/ps2epsi line 35:
	  *.epsf)	base=`basename "${infile}" .epsf` ;;
                             ^--------------------------^ SC2006: Use $(...) notation instead of legacy backticked `...`.

Did you mean: 
	  *.epsf)	base=$(basename "${infile}" .epsf) ;;


In /usr/bin/ps2epsi line 36:
	  *)		base=`basename "${infile}"` ;;
                             ^--------------------^ SC2006: Use $(...) notation instead of legacy backticked `...`.

Did you mean: 
	  *)		base=$(basename "${infile}") ;;

For more information:
  https://www.shellcheck.net/wiki/SC2166 -- Prefer [ p ] || [ q ] as [ p -o q...
  https://www.shellcheck.net/wiki/SC2086 -- Double quote to prevent globbing ...
  https://www.shellcheck.net/wiki/SC2006 -- Use $(...) notation instead of le...