Event not found in sed call in csh script

Question

I tried the code as given on delete text between curly brackets

however I am facing this different error regarding event in sed.

file contains:

This is {
{the multiline
text} file }
that wants
{ to {be
changed}
} anyway.

sed ':again;$!N;$!b again; s/{[^}]*}//g' file

what is supposively going wrong in the workout?

Error

N: Event not found.

Was it really necessary to make a screenshot instead of providing the console content as text which the readers could copy and paste? — Hauke Laging, Dec 01 '14 at 09:38
I provided the link and the snapshot , to state that I did exactly same. sorry for inconvenience..
many-times when i perform simple copy paste from windows to unix terminal some of special characters do get deleted . I don't know how. I am using citrix based apps to run UNIX — JigarGandhi, Dec 01 '14 at 09:43

score 7 · Accepted Answer · answered Dec 01 '14 at 10:31

7

You have to escape ! to prevent csh/tcsh from performing history expansion. They still do history expansion though you wrote ! in single quote.

Try:

sed ':again;$\!N;$\!b again; s/{[^}]*}//g' file

Or you can write a script an call with -f script.sed (Read sed FAQ).

answered Dec 01 '14 at 10:31

cuonglm

153,898

You can also disable history expansion with set histchars. The histchars variable contains which characters to use for history expansion (you can reset this to the default with set histchars = "!^"). – Martin Tournoij Dec 01 '14 at 12:36

score -1 · Answer 2 · answered Dec 01 '14 at 09:56

-1

I am not familiar with tcsh but this sounds like a history expansion problem. In bash single quotes prevent history expansion, maybe in tcsh they don't.

You may disable history expansion (I don't know how to do that, though; in bash this is done by set +H).

Another option: Backslash escapes should work. Try

sed_code=":again;\$\!N;\$\!b again; s/{[^}]*}//g"
sed "$sed_code" file

answered Dec 01 '14 at 09:56

Hauke Laging

90,279

I am unable to assign sed_code=":again;\$\!N;\$\!b again; s/{[^}]*}//g" as the variable is not assigned.
here is one article regarding it. variable trouble
– JigarGandhi Dec 01 '14 at 10:16
@JigarGandhi This is how it would be done in bash. You have to translate it to tcsh code yourself (or wait for someone who is familiar with it). – Hauke Laging Dec 01 '14 at 10:19
It seems to be a law that every (t)csh question has at least one answer from a (knowledgeable) bash/zsh user, with an answer that doesn't apply to tcsh, or doesn't work... – Martin Tournoij Dec 01 '14 at 11:49
@Carpetsmoker But you do realize, I hope, that my answer was the first, identified the problem correctly, and pointed at the correct solution. It would be ridiculous to suggest this answer had better not been given. – Hauke Laging Dec 01 '14 at 12:24
It doesn't point to a correct solution, since set +H doesn't work in tcsh, and neither does sed_code=":again;\$\!N;\$\!b again; s/{[^}]*}//g". You did make a good estimate as to the problem, but IMHO this is not enough to qualify as a decent answer. – Martin Tournoij Dec 01 '14 at 12:34

Event not found in sed call in csh script

2 Answers2

Linked