sub-shell inside sed

up vote
1
down vote

favorite

I can append to the start of a file fine with:

sed -i '1s/^/wordn/' file

I'm reading that if I use double quotes I can expand variables, so I try:

sed -i "1s/^/$(printenv)n/" file

I end up getting back:

sed: -e expression #1, char 15: unterminated `s' command

What is happening here. Is it related to the contents of the variable or something else?

edited Oct 14 '17 at 15:26

don_crissti

47k15124154

asked Oct 14 '17 at 14:56

Philip Kirkbride

2,3022470

$(command) is not a variable...
â€“Â don_crissti
Oct 14 '17 at 15:27

add a commentÂ |Â

up vote
1
down vote

favorite

I can append to the start of a file fine with:

sed -i '1s/^/wordn/' file

I'm reading that if I use double quotes I can expand variables, so I try:

sed -i "1s/^/$(printenv)n/" file

I end up getting back:

sed: -e expression #1, char 15: unterminated `s' command

What is happening here. Is it related to the contents of the variable or something else?

edited Oct 14 '17 at 15:26

don_crissti

47k15124154

asked Oct 14 '17 at 14:56

Philip Kirkbride

2,3022470

$(command) is not a variable...
â€“Â don_crissti
Oct 14 '17 at 15:27

add a commentÂ |Â

up vote
1
down vote

favorite

I can append to the start of a file fine with:

sed -i '1s/^/wordn/' file

I'm reading that if I use double quotes I can expand variables, so I try:

sed -i "1s/^/$(printenv)n/" file

I end up getting back:

sed: -e expression #1, char 15: unterminated `s' command

What is happening here. Is it related to the contents of the variable or something else?

edited Oct 14 '17 at 15:26

don_crissti

47k15124154

asked Oct 14 '17 at 14:56

Philip Kirkbride

2,3022470

I can append to the start of a file fine with:

sed -i '1s/^/wordn/' file

I'm reading that if I use double quotes I can expand variables, so I try:

sed -i "1s/^/$(printenv)n/" file

I end up getting back:

sed: -e expression #1, char 15: unterminated `s' command

What is happening here. Is it related to the contents of the variable or something else?

edited Oct 14 '17 at 15:26

don_crissti

47k15124154

asked Oct 14 '17 at 14:56

Philip Kirkbride

2,3022470

edited Oct 14 '17 at 15:26

don_crissti

47k15124154

edited Oct 14 '17 at 15:26

don_crissti

47k15124154

edited Oct 14 '17 at 15:26

don_crissti

47k15124154

asked Oct 14 '17 at 14:56

Philip Kirkbride

2,3022470

asked Oct 14 '17 at 14:56

Philip Kirkbride

2,3022470

asked Oct 14 '17 at 14:56

Philip Kirkbride

2,3022470

$(command) is not a variable...
â€“Â don_crissti
Oct 14 '17 at 15:27

add a commentÂ |Â

$(command) is not a variable...
â€“Â don_crissti
Oct 14 '17 at 15:27

$(command) is not a variable...
â€“Â don_crissti
Oct 14 '17 at 15:27

add a commentÂ |Â

2 Answers
2

active

oldest

votes

up vote
6
down vote

accepted

I think the following would work:

sed -i '1 e printenv' file

From the GNU sed manual:

'e COMMAND'
 Executes COMMAND and sends its output to the output stream. The
 command can run across multiple lines, all but the last ending with
 a back-slash.

Alternatively, you can use cat, but this requires creating a temporary file:

cat <(printenv) file > temporary_file; mv temporary_file file

If the package moreutils is installed on your machine, you can avoid creating a temporary file manually by using sponge:

cat <(printenv) file | sponge file

edited Oct 14 '17 at 16:58

answered Oct 14 '17 at 15:11

Rastapopoulos

518112

add a commentÂ |Â

up vote
5
down vote

To insert the contents before line 1:

ed -s file <<< $'0r !printenvnwq'

To insert the contents after line 1:

ed -s file <<< $'1r !printenvnwq'

answered Oct 14 '17 at 15:12

Jeff Schaller

32.1k849109

add a commentÂ |Â

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2 Answers
2

active

oldest

votes

2 Answers
2

active

oldest

votes

up vote
6
down vote

accepted

I think the following would work:

sed -i '1 e printenv' file

From the GNU sed manual:

'e COMMAND'
 Executes COMMAND and sends its output to the output stream. The
 command can run across multiple lines, all but the last ending with
 a back-slash.

Alternatively, you can use cat, but this requires creating a temporary file:

cat <(printenv) file > temporary_file; mv temporary_file file

If the package moreutils is installed on your machine, you can avoid creating a temporary file manually by using sponge:

cat <(printenv) file | sponge file

edited Oct 14 '17 at 16:58

answered Oct 14 '17 at 15:11

Rastapopoulos

518112

add a commentÂ |Â

up vote
6
down vote

accepted

I think the following would work:

sed -i '1 e printenv' file

From the GNU sed manual:

'e COMMAND'
 Executes COMMAND and sends its output to the output stream. The
 command can run across multiple lines, all but the last ending with
 a back-slash.

Alternatively, you can use cat, but this requires creating a temporary file:

cat <(printenv) file > temporary_file; mv temporary_file file

If the package moreutils is installed on your machine, you can avoid creating a temporary file manually by using sponge:

cat <(printenv) file | sponge file

edited Oct 14 '17 at 16:58

answered Oct 14 '17 at 15:11

Rastapopoulos

518112

add a commentÂ |Â

up vote
6
down vote

accepted

I think the following would work:

sed -i '1 e printenv' file

From the GNU sed manual:

'e COMMAND'
 Executes COMMAND and sends its output to the output stream. The
 command can run across multiple lines, all but the last ending with
 a back-slash.

Alternatively, you can use cat, but this requires creating a temporary file:

cat <(printenv) file > temporary_file; mv temporary_file file

If the package moreutils is installed on your machine, you can avoid creating a temporary file manually by using sponge:

cat <(printenv) file | sponge file

edited Oct 14 '17 at 16:58

answered Oct 14 '17 at 15:11

Rastapopoulos

518112

I think the following would work:

sed -i '1 e printenv' file

From the GNU sed manual:

'e COMMAND'
 Executes COMMAND and sends its output to the output stream. The
 command can run across multiple lines, all but the last ending with
 a back-slash.

Alternatively, you can use cat, but this requires creating a temporary file:

cat <(printenv) file > temporary_file; mv temporary_file file

If the package moreutils is installed on your machine, you can avoid creating a temporary file manually by using sponge:

cat <(printenv) file | sponge file

edited Oct 14 '17 at 16:58

answered Oct 14 '17 at 15:11

Rastapopoulos

518112

edited Oct 14 '17 at 16:58

answered Oct 14 '17 at 15:11

Rastapopoulos

518112

answered Oct 14 '17 at 15:11

Rastapopoulos

518112

answered Oct 14 '17 at 15:11

Rastapopoulos

518112

add a commentÂ |Â

up vote
5
down vote

To insert the contents before line 1:

ed -s file <<< $'0r !printenvnwq'

To insert the contents after line 1:

ed -s file <<< $'1r !printenvnwq'

answered Oct 14 '17 at 15:12

Jeff Schaller

32.1k849109

add a commentÂ |Â

up vote
5
down vote

To insert the contents before line 1:

ed -s file <<< $'0r !printenvnwq'

To insert the contents after line 1:

ed -s file <<< $'1r !printenvnwq'

answered Oct 14 '17 at 15:12

Jeff Schaller

32.1k849109

add a commentÂ |Â

up vote
5
down vote

To insert the contents before line 1:

ed -s file <<< $'0r !printenvnwq'

To insert the contents after line 1:

ed -s file <<< $'1r !printenvnwq'

answered Oct 14 '17 at 15:12

Jeff Schaller

32.1k849109

To insert the contents before line 1:

ed -s file <<< $'0r !printenvnwq'

To insert the contents after line 1:

ed -s file <<< $'1r !printenvnwq'

answered Oct 14 '17 at 15:12

Jeff Schaller

32.1k849109

answered Oct 14 '17 at 15:12

Jeff Schaller

32.1k849109

answered Oct 14 '17 at 15:12

Jeff Schaller

32.1k849109

answered Oct 14 '17 at 15:12

Jeff Schaller

32.1k849109

add a commentÂ |Â

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