CODEWITHSUNDEEP
shellsedcsh
nav_jan
nav_jan

Reputation: 2553

removing new line character from incoming stream using sed

I am new to shell scripting and i am trying to remove new line character from each line using SED. this is what i have done so far :

printf "{new\nto\nlinux}" | sed ':a;N;s/\n/ /g'

removes only Ist new line character. I somewhere found this command :

printf "{new\nto\nlinux}" | sed ':a;N;$!ba;s/\n/ /g'

but it gives :"ba: Event not found."

if i do:

printf "{new\nto\nlinux}" | sed ':a;N;s/\n/ /g' | sed ':a;N;s/\n/ /g'

then it gives correct output but i am looking for something better as i am not sure how many new character i will get when i run the script. incoming stream is from echo or printf or some variable in script.

Upvotes: 49

Views: 123771

Answers (3)

Rublacava
Rublacava

Reputation: 519

Use perl instead of sed. perl is similar to sed:

ubuntu@ubuntu:/$ printf "{new\nto\nlinux}" | sed 's/\n/ /g'; echo ''
{new
to
linux}
ubuntu@ubuntu:/$ printf "{new\nto\nlinux}" | perl -pe 's/\n/ /g'; echo ''
{new to linux}
ubuntu@ubuntu:/$ echo -e "new\nto\nlinux\ntest\n1\n2 3" | perl -pe 's/\n/_ _/g'; echo ''
new_ _to_ _linux_ _test_ _1_ _2 3_ _
ubuntu@ubuntu:/$

Upvotes: 0

William Pursell
William Pursell

Reputation: 212248

To remove newlines, use tr:

tr -d '\n'

If you want to replace each newline with a single space:

tr '\n' ' '

The error ba: Event not found is coming from csh, and is due to csh trying to match !ba in your history list. You can escape the ! and write the command:

sed ':a;N;$\!ba;s/\n/ /g'  # Suitable for csh only!!

but sed is the wrong tool for this, and you would be better off using a shell that handles quoted strings more reasonably. That is, stop using csh and start using bash.

Upvotes: 111

potong
potong

Reputation: 58420

This might work for you:

printf "{new\nto\nlinux}" | paste -sd' '            
{new to linux}

or:

printf "{new\nto\nlinux}" | tr '\n' ' '            
{new to linux}

or:

printf "{new\nto\nlinux}" |sed -e ':a' -e '$!{' -e 'N' -e 'ba' -e '}' -e 's/\n/ /g'
{new to linux}

Upvotes: 8

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