tsharley · February 15, 2023 20:28
diff --git a/gistfile1.txt b/gistfile1.txt
 #!/bin/bash
 # generate-script.sh
 # A script that generates another script using a heredoc.
 # More examples and use cases at https://tldp.org/LDP/abs/html/here-docs.html.
 # Based on an idea by Albert Reiner.

 OUTFILE=generated.sh         # Name of the file to generate.
 # -----------------------------------------------------------
 # 'Here document containing the body of the generated script.
 (
 cat <<'EOF'
 #!/bin/bash

 echo "This is a generated shell script."
 #  Note that since we are inside a subshell,
 #+ we can't access variables in the "outside" script.

 echo "Generated file will be named: $OUTFILE"
 #  Above line will not work as normally expected
 #+ because parameter expansion has been disabled.
 #  Instead, the result is literal output.

 a=7
 b=3

 let "c = $a * $b"
 echo "c = $c"

 exit 0
 EOF
 ) > $OUTFILE
 # -----------------------------------------------------------

 #  Quoting the 'limit string' prevents variable expansion
 #  within the body of the above 'here document.'
 #  This permits outputting literal strings in the output file.

 if [ -f "$OUTFILE" ]
 then
  chmod 755 $OUTFILE
  # Make the generated file executable.
 else
  echo "Problem in creating file: \"$OUTFILE\""
 fi

 #  This method also works for generating
 #+ C programs, Perl programs, Python programs, Makefiles,
 #+ and the like.

 exit 0
	#!/bin/bash
	# generate-script.sh
	# A script that generates another script using a heredoc.
	# More examples and use cases at https://tldp.org/LDP/abs/html/here-docs.html.
	# Based on an idea by Albert Reiner.

	OUTFILE=generated.sh # Name of the file to generate.
	# -----------------------------------------------------------
	# 'Here document containing the body of the generated script.
	(
	cat <<'EOF'
	#!/bin/bash

	echo "This is a generated shell script."
	# Note that since we are inside a subshell,
	#+ we can't access variables in the "outside" script.

	echo "Generated file will be named: $OUTFILE"
	# Above line will not work as normally expected
	#+ because parameter expansion has been disabled.
	# Instead, the result is literal output.

	a=7
	b=3

	let "c = $a * $b"
	echo "c = $c"

	exit 0
	EOF
	) > $OUTFILE
	# -----------------------------------------------------------

	# Quoting the 'limit string' prevents variable expansion
	# within the body of the above 'here document.'
	# This permits outputting literal strings in the output file.

	if [ -f "$OUTFILE" ]
	then
	chmod 755 $OUTFILE
	# Make the generated file executable.
	else
	echo "Problem in creating file: \"$OUTFILE\""
	fi

	# This method also works for generating
	#+ C programs, Perl programs, Python programs, Makefiles,
	#+ and the like.

	exit 0
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