CODEWITHSUNDEEP
sedsh
paul23
paul23

Reputation: 9455

Sed with variables and spaces

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?

Upvotes: 0

Views: 945

Answers (3)

glenn jackman
glenn jackman

Reputation: 247210

Using ed with commands read from a here-doc

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

Upvotes: 0

Marko
Marko

Reputation: 93

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

Upvotes: 0

sneep
sneep

Reputation: 1918

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).

Upvotes: 2

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