Keep backslash and linebreak with EOF

up vote
3
down vote

favorite

I'm creating a file with EOF like this:

cat <<EOF > Dockerfile
RUN apt-get update -y 
 && apt-get install -y 
 bsdtar 
 git 
 locales
EOF

But the result is:

RUN apt-get update -y && apt-get install -y bsdtar git locales

I want to keep the backslash and the linebreak

asked Oct 21 '17 at 7:18

user3142695

362816

1

Double the backslashes; or quote-or-backslash the EOF (or any char(s) in it) to prevent all modification of the heredoc. See the bash manual section on heredocs
â€“Â dave_thompson_085
Oct 21 '17 at 7:24

add a commentÂ |Â

up vote
3
down vote

favorite

I'm creating a file with EOF like this:

cat <<EOF > Dockerfile
RUN apt-get update -y 
 && apt-get install -y 
 bsdtar 
 git 
 locales
EOF

But the result is:

RUN apt-get update -y && apt-get install -y bsdtar git locales

I want to keep the backslash and the linebreak

asked Oct 21 '17 at 7:18

user3142695

362816

1

Double the backslashes; or quote-or-backslash the EOF (or any char(s) in it) to prevent all modification of the heredoc. See the bash manual section on heredocs
â€“Â dave_thompson_085
Oct 21 '17 at 7:24

add a commentÂ |Â

up vote
3
down vote

favorite

I'm creating a file with EOF like this:

cat <<EOF > Dockerfile
RUN apt-get update -y 
 && apt-get install -y 
 bsdtar 
 git 
 locales
EOF

But the result is:

RUN apt-get update -y && apt-get install -y bsdtar git locales

I want to keep the backslash and the linebreak

asked Oct 21 '17 at 7:18

user3142695

362816

I'm creating a file with EOF like this:

cat <<EOF > Dockerfile
RUN apt-get update -y 
 && apt-get install -y 
 bsdtar 
 git 
 locales
EOF

But the result is:

RUN apt-get update -y && apt-get install -y bsdtar git locales

I want to keep the backslash and the linebreak

asked Oct 21 '17 at 7:18

user3142695

362816

asked Oct 21 '17 at 7:18

user3142695

362816

asked Oct 21 '17 at 7:18

user3142695

362816

asked Oct 21 '17 at 7:18

user3142695

362816

1

Double the backslashes; or quote-or-backslash the EOF (or any char(s) in it) to prevent all modification of the heredoc. See the bash manual section on heredocs
â€“Â dave_thompson_085
Oct 21 '17 at 7:24

add a commentÂ |Â

1

Double the backslashes; or quote-or-backslash the EOF (or any char(s) in it) to prevent all modification of the heredoc. See the bash manual section on heredocs
â€“Â dave_thompson_085
Oct 21 '17 at 7:24

Double the backslashes; or quote-or-backslash the EOF (or any char(s) in it) to prevent all modification of the heredoc. See the bash manual section on heredocs
â€“Â dave_thompson_085
Oct 21 '17 at 7:24

add a commentÂ |Â

1 Answer
1

active

oldest

votes

up vote
2
down vote

accepted

You need to quote the EOF token:

cat <<"EOF" > Dockerfile
RUN apt-get update -y 
 && apt-get install -y 
 bsdtar 
 git 
 locales
EOF

If you want to expand variables too, you need to escape the backslashes and not use any quotes.

Here's the corresponding man bash section.

 [n]<<[-]word
 here-document
 delimiter

 No parameter and variable expansion, command substitution, arithmetic
 expansion, or pathname expansion is performed on word. If any part of
 word is quoted, the delimiter is the result of quote removal on word,
 and the lines in the here-document are not expanded. If word is
 unquoted, all lines of the here-document are subjected to parameter
 expansion, command substitution, and arithmetic expansion, the characÃ¢Â€Â
 ter sequence <newline> is ignored, and must be used to quote the
 characters , $, and `.

edited Oct 21 '17 at 9:37

answered Oct 21 '17 at 7:24

Tomasz

8,06552560

But what do I have to do if I need to use some variables (not shown in my example code)?
â€“Â user3142695
Oct 21 '17 at 7:50

They will get expanded as in the common shell double quoting. If this is not desired, use single quotes, eg. cat <<'EOF' > Dockerfile.
â€“Â Tomasz
Oct 21 '17 at 7:52

I think that's not the case (i.e. with double quotes around EOF, the variables will not be expanded). Are you sure? The correct answer is in the comment by @dave_thompson_085 : double the backslashes.
â€“Â Rastapopoulos
Oct 21 '17 at 9:25

@Rastapopoulos I thought so, but it looks like I was wrong.
â€“Â Tomasz
Oct 21 '17 at 9:28

@user3142695 As in the comment above, double quoting stops expansion too. So to both expand variables and keep the backslashes, you need to escape the backslashes and not use any quotes.
â€“Â Tomasz
Oct 21 '17 at 9:32

add a commentÂ |Â

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1 Answer
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oldest

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1 Answer
1

active

oldest

votes

up vote
2
down vote

accepted

You need to quote the EOF token:

cat <<"EOF" > Dockerfile
RUN apt-get update -y 
 && apt-get install -y 
 bsdtar 
 git 
 locales
EOF

If you want to expand variables too, you need to escape the backslashes and not use any quotes.

Here's the corresponding man bash section.

 [n]<<[-]word
 here-document
 delimiter

 No parameter and variable expansion, command substitution, arithmetic
 expansion, or pathname expansion is performed on word. If any part of
 word is quoted, the delimiter is the result of quote removal on word,
 and the lines in the here-document are not expanded. If word is
 unquoted, all lines of the here-document are subjected to parameter
 expansion, command substitution, and arithmetic expansion, the characÃ¢Â€Â
 ter sequence <newline> is ignored, and must be used to quote the
 characters , $, and `.

edited Oct 21 '17 at 9:37

answered Oct 21 '17 at 7:24

Tomasz

8,06552560

But what do I have to do if I need to use some variables (not shown in my example code)?
â€“Â user3142695
Oct 21 '17 at 7:50

They will get expanded as in the common shell double quoting. If this is not desired, use single quotes, eg. cat <<'EOF' > Dockerfile.
â€“Â Tomasz
Oct 21 '17 at 7:52

I think that's not the case (i.e. with double quotes around EOF, the variables will not be expanded). Are you sure? The correct answer is in the comment by @dave_thompson_085 : double the backslashes.
â€“Â Rastapopoulos
Oct 21 '17 at 9:25

@Rastapopoulos I thought so, but it looks like I was wrong.
â€“Â Tomasz
Oct 21 '17 at 9:28

@user3142695 As in the comment above, double quoting stops expansion too. So to both expand variables and keep the backslashes, you need to escape the backslashes and not use any quotes.
â€“Â Tomasz
Oct 21 '17 at 9:32

add a commentÂ |Â

up vote
2
down vote

accepted

You need to quote the EOF token:

cat <<"EOF" > Dockerfile
RUN apt-get update -y 
 && apt-get install -y 
 bsdtar 
 git 
 locales
EOF

If you want to expand variables too, you need to escape the backslashes and not use any quotes.

Here's the corresponding man bash section.

 [n]<<[-]word
 here-document
 delimiter

 No parameter and variable expansion, command substitution, arithmetic
 expansion, or pathname expansion is performed on word. If any part of
 word is quoted, the delimiter is the result of quote removal on word,
 and the lines in the here-document are not expanded. If word is
 unquoted, all lines of the here-document are subjected to parameter
 expansion, command substitution, and arithmetic expansion, the characÃ¢Â€Â
 ter sequence <newline> is ignored, and must be used to quote the
 characters , $, and `.

edited Oct 21 '17 at 9:37

answered Oct 21 '17 at 7:24

Tomasz

8,06552560

But what do I have to do if I need to use some variables (not shown in my example code)?
â€“Â user3142695
Oct 21 '17 at 7:50

They will get expanded as in the common shell double quoting. If this is not desired, use single quotes, eg. cat <<'EOF' > Dockerfile.
â€“Â Tomasz
Oct 21 '17 at 7:52

I think that's not the case (i.e. with double quotes around EOF, the variables will not be expanded). Are you sure? The correct answer is in the comment by @dave_thompson_085 : double the backslashes.
â€“Â Rastapopoulos
Oct 21 '17 at 9:25

@Rastapopoulos I thought so, but it looks like I was wrong.
â€“Â Tomasz
Oct 21 '17 at 9:28

@user3142695 As in the comment above, double quoting stops expansion too. So to both expand variables and keep the backslashes, you need to escape the backslashes and not use any quotes.
â€“Â Tomasz
Oct 21 '17 at 9:32

add a commentÂ |Â

up vote
2
down vote

accepted

You need to quote the EOF token:

cat <<"EOF" > Dockerfile
RUN apt-get update -y 
 && apt-get install -y 
 bsdtar 
 git 
 locales
EOF

If you want to expand variables too, you need to escape the backslashes and not use any quotes.

Here's the corresponding man bash section.

 [n]<<[-]word
 here-document
 delimiter

 No parameter and variable expansion, command substitution, arithmetic
 expansion, or pathname expansion is performed on word. If any part of
 word is quoted, the delimiter is the result of quote removal on word,
 and the lines in the here-document are not expanded. If word is
 unquoted, all lines of the here-document are subjected to parameter
 expansion, command substitution, and arithmetic expansion, the characÃ¢Â€Â
 ter sequence <newline> is ignored, and must be used to quote the
 characters , $, and `.

edited Oct 21 '17 at 9:37

answered Oct 21 '17 at 7:24

Tomasz

8,06552560

You need to quote the EOF token:

cat <<"EOF" > Dockerfile
RUN apt-get update -y 
 && apt-get install -y 
 bsdtar 
 git 
 locales
EOF

If you want to expand variables too, you need to escape the backslashes and not use any quotes.

Here's the corresponding man bash section.

 [n]<<[-]word
 here-document
 delimiter

 No parameter and variable expansion, command substitution, arithmetic
 expansion, or pathname expansion is performed on word. If any part of
 word is quoted, the delimiter is the result of quote removal on word,
 and the lines in the here-document are not expanded. If word is
 unquoted, all lines of the here-document are subjected to parameter
 expansion, command substitution, and arithmetic expansion, the characÃ¢Â€Â
 ter sequence <newline> is ignored, and must be used to quote the
 characters , $, and `.

edited Oct 21 '17 at 9:37

answered Oct 21 '17 at 7:24

Tomasz

8,06552560

edited Oct 21 '17 at 9:37

answered Oct 21 '17 at 7:24

Tomasz

8,06552560

answered Oct 21 '17 at 7:24

Tomasz

8,06552560

answered Oct 21 '17 at 7:24

Tomasz

8,06552560

But what do I have to do if I need to use some variables (not shown in my example code)?
â€“Â user3142695
Oct 21 '17 at 7:50

They will get expanded as in the common shell double quoting. If this is not desired, use single quotes, eg. cat <<'EOF' > Dockerfile.
â€“Â Tomasz
Oct 21 '17 at 7:52

I think that's not the case (i.e. with double quotes around EOF, the variables will not be expanded). Are you sure? The correct answer is in the comment by @dave_thompson_085 : double the backslashes.
â€“Â Rastapopoulos
Oct 21 '17 at 9:25

@Rastapopoulos I thought so, but it looks like I was wrong.
â€“Â Tomasz
Oct 21 '17 at 9:28

@user3142695 As in the comment above, double quoting stops expansion too. So to both expand variables and keep the backslashes, you need to escape the backslashes and not use any quotes.
â€“Â Tomasz
Oct 21 '17 at 9:32

add a commentÂ |Â

But what do I have to do if I need to use some variables (not shown in my example code)?
â€“Â user3142695
Oct 21 '17 at 7:50

They will get expanded as in the common shell double quoting. If this is not desired, use single quotes, eg. cat <<'EOF' > Dockerfile.
â€“Â Tomasz
Oct 21 '17 at 7:52

I think that's not the case (i.e. with double quotes around EOF, the variables will not be expanded). Are you sure? The correct answer is in the comment by @dave_thompson_085 : double the backslashes.
â€“Â Rastapopoulos
Oct 21 '17 at 9:25

@Rastapopoulos I thought so, but it looks like I was wrong.
â€“Â Tomasz
Oct 21 '17 at 9:28

@user3142695 As in the comment above, double quoting stops expansion too. So to both expand variables and keep the backslashes, you need to escape the backslashes and not use any quotes.
â€“Â Tomasz
Oct 21 '17 at 9:32

But what do I have to do if I need to use some variables (not shown in my example code)?
â€“Â user3142695
Oct 21 '17 at 7:50

They will get expanded as in the common shell double quoting. If this is not desired, use single quotes, eg. cat <<'EOF' > Dockerfile.
â€“Â Tomasz
Oct 21 '17 at 7:52

I think that's not the case (i.e. with double quotes around EOF, the variables will not be expanded). Are you sure? The correct answer is in the comment by @dave_thompson_085 : double the backslashes.
â€“Â Rastapopoulos
Oct 21 '17 at 9:25

@Rastapopoulos I thought so, but it looks like I was wrong.
â€“Â Tomasz
Oct 21 '17 at 9:28

@user3142695 As in the comment above, double quoting stops expansion too. So to both expand variables and keep the backslashes, you need to escape the backslashes and not use any quotes.
â€“Â Tomasz
Oct 21 '17 at 9:32

add a commentÂ |Â

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