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If the here document should only be added if none of it is present, you can use grep:

cat <<-"EOF1" >> myPath/myFile.append
    content...
EOF1
if ! grep -F -q -f myPath/myFile{.append,}; then
    cat myPath/myFile.append >> myPath/myFile
fi

To understand this, consider the following.

• grep -F -q -f myPath/myFile{.append,} is expanded by the shell to grep -F -q -f myPath/myFile.append myPath/myFile.

• The grep command searches myPath/myFile (the file to which the text should be added if necessary) for any fixed string (-F) contained in myPath/myFile.append (the file containing the text to add), reading one pattern per line (-f), and indicates whether it finds any only by its exit code, with no output (-q).

• The result is then negated !, so that the if block’s then part is only run if grep doesn’t find anything.

If the here document should only be added if none of it is present, you can use grep:

cat <<-"EOF1" > myPath/myFile.append
    content...
EOF1
if ! grep -F -q -f myPath/myFile{.append,}; then
    cat myPath/myFile.append >> myPath/myFile
fi

To understand this, consider the following.

• grep -F -q -f myPath/myFile{.append,} is expanded by the shell to grep -F -q -f myPath/myFile.append myPath/myFile.

• The grep command searches myPath/myFile (the file to which the text should be added if necessary) for any fixed string (-F) contained in myPath/myFile.append (the file containing the text to add), reading one pattern per line (-f), and indicates whether it finds any only by its exit code, with no output (-q).

• The result is then negated !, so that the if block’s then part is only run if grep doesn’t find anything.

If the here document should only be added if none of it is present, you can use grep:

cat <<-"EOF1" >> myPath/myFile.append
if ! grep -F -q -f myPath/myFile{.append,}; then
    cat myPath/myFile.append >> myPath/myFile
fi

To understand this, consider the following.

• grep -F -q -f myPath/myFile{.append,} is expanded by the shell to grep -F -q -f myPath/myFile.append myPath/myFile.

• The grep command searches myPath/myFile (the file to which the text should be added if necessary) for any fixed string (-F) contained in myPath/myFile.append (the file containing the text to add), reading one pattern per line (-f), and indicates whether it finds any only by its exit code, with no output (-q).

• The result is then negated !, so that the if block’s then part is only run if grep doesn’t find anything.

If the here document should only be added if none of it is present, you can use grep:

cat <<-"EOF1" >> myPath/myFile.append
    content...
EOF1
if ! grep -F -q -f myPath/myFile{.append,}; then
    cat myPath/myFile.append >> myPath/myFile
fi

To understand this, consider the following.

• grep -F -q -f myPath/myFile{.append,} is expanded by the shell to grep -F -q -f myPath/myFile.append myPath/myFile.

• The grep command searches myPath/myFile (the file to which the text should be added if necessary) for any fixed string (-F) contained in myPath/myFile.append (the file containing the text to add), reading one pattern per line (-f), and indicates whether it finds any only by its exit code, with no output (-q).

• The result is then negated !, so that the if block’s then part is only run if grep doesn’t find anything.

If the here document should only be added if none of it is present, you can use grep:

cat <<-"EOF1" >> myPath/myFile.append
if ! grep -F -q -f myPath/myFile{.append,}; then
    cat myPath/myFile.append >> myPath/myFile
fi

To understand this, consider the following.

• grep -F -q -f myPath/myFile{.append,} is expanded by the shell to grep -F -q -f myPath/myFile.append myPath/myFile.

• The grep command searches myPath/myFile (the file to which the text should be added if necessary) for any fixed string (-F) contained in myPath/myFile.append (the file containing the text to add), reading one pattern per line (-f), and indicates whether it finds any only by its exit code, with no output (-q).

• The result is then negated !, so that the if block’s then part is only run if grep doesn’t find anything.

If the here document should only be added if none of it is present, you can use grep:

cat <<-"EOF1" >> myPath/myFile.append
if ! grep -F -q -f myPath/myFile{.append,}; then
    cat myPath/myFile.append >> myPath/myFile
fi

To understand this, consider the following.

• grep -F -q -f myPath/myFile{.append,} is expanded by the shell to grep -F -q -f myPath/myFile.append myPath/myFile.

• The grep command searches myPath/myFile (the file to which the text should be added if necessary) for any fixed string (-F) contained in myPath/myFile.append (the file containing the text to add), reading one pattern per line (-f), and indicates whether it finds any only by its exit code, with no output (-q).

• The result is then negated !, so that the if block’s then part is only run if grep doesn’t find anything.