Sed with variables and spaces

Question

How would I use a variable -containing spaces- as values in sed? - I'm using sh (not bash) as terminal.

What I'm trying to do (insert a b c in the first line of the file):

TMP='a b c'
sed -e '1i'${TMP} tmp.txt

However this errors with the message

dynamic-config-manager-nginx.sh: -: not found

And in the files I only see the first a inserted. - It seems that sed is exiting too early. "forcing" quotes around the string like below also doesn't work, with " command not found sed -e '"1e'${TMP}'"' tmp.txt

So how do I make this work?

also, what is your sed version, as far as I know, you need backslash and newline after `i` command for non-GNU versions.. see https://www.gnu.org/software/sed/manual/sed.html#Other-Commands — Sundeep, Mar 24 '18 at 06:09

score 2 · Accepted Answer · answered Mar 24 '18 at 06:10

2

I think you want the -i option, to edit inplace. This gets us here:

$ sed -i -e '1i'${TMP} tmp.txt
sed: can't read b: No such file or directory
sed: can't read c: No such file or directory

${TMP} will be expanded to multiple arguments to sed. We want it all in a single string though:

sed -i -e "1i${TMP}" tmp.txt

One more caveat: tmp.txt must contain at least one line. If you know that tmp.txt doesn't exist or is an empty file, maybe do something like echo > tmp.txt first (warning: this will overwrite the file if it contained something).

answered Mar 24 '18 at 06:10

sneep

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this assumes GNU sed, for both `-i` option as well as `i` command... see https://stackoverflow.com/questions/5694228/sed-in-place-flag-that-works-both-on-mac-bsd-and-linux and https://www.gnu.org/software/sed/manual/sed.html#Other-Commands – Sundeep Mar 24 '18 at 06:12
Ah. Didn't know that. : – sneep Mar 24 '18 at 06:16

score 0 · Answer 2 · answered Mar 24 '18 at 06:32

0

Solution with awk:

#!/bin/sh
TMP="a b c"
exec 3<> tmp.txt && awk -v TEXT="$TMP" 'BEGIN {print TEXT}{print}' tmp.txt >&3

solution from John Mee

answered Mar 24 '18 at 06:32

Marko

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1
7

score 0 · Answer 3 · answered Mar 24 '18 at 10:57

0

Using ed with commands read from a here-doc

ed tmp.txt <<END_ED_COMMANDS
1i
$TMP
.
w
q
END_ED_COMMANDS

answered Mar 24 '18 at 10:57

glenn jackman

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38
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Sed with variables and spaces

3 Answers3