How to remove Ctrl-M from files where dos2unix, perl, tr, and sed are not present?

Question

Suppose you are working on a very old unix server where dos2unix, perl, tr, and sed are not present. How can you convert files from dos to unix format?

How old does a unix server have to be to not have tr and sed ? sed is old........ iirc, — xenoterracide, Nov 07 '10 at 23:25
Would ex or ed be available on a system like that? I would'nt call it unix if there is no tr or sed. — MattBianco, Mar 31 '11 at 06:52
No sed? Really!? Out of interest, what is the system? As Gilles and MattBianco point out, it would probably still have ed at least. — Mikel, Mar 31 '11 at 21:03

score 12 · Accepted Answer · answered Aug 12 '10 at 15:58

12

I think you are referring to removing the caret-M at the end of lines. You can use search and replace in vi to do this.

In vi I normally do: (where "^" represents CTRL):

:%s/^V^M//g

Which shows on the screen as:

:%s/^M//g

answered Aug 12 '10 at 15:58

jjclarkson

2,147

thanks that worked :). I think its a very portable solution. – Hemant Aug 12 '10 at 16:06
4

You can also use sed to do the same thing w/out having to vim the file: sed -e '%s/^V^M//g' filename
That also will show on the screen as sed e '%s/^M//g' filename In general, if you can search/replace it in vim, the command is virtually the same in sed. – gabe. Aug 12 '10 at 19:09
2

@gabe: the sed solution is actually even more portable +1 :) – wzzrd Aug 12 '10 at 20:54
@wzzrd, sed and vi are both specified by POSIX, and that vi command doesn't use any Vim extensions. – Wildcard Apr 16 '16 at 02:11
@jjclarkson what does ^V and '^M' mean? – cokedude Apr 28 '16 at 22:10
@gabe. is my sed to old to do this $ sed -e '%s/^M//g' cookies sed: -e expression #1, char 1: unknown command:%' ` ? – cokedude Apr 28 '16 at 22:11

score 6 · Answer 2 · answered Mar 31 '11 at 20:42

A server without tr or sed would have to be really old, or missing some basic commands. Hopefully ed is there; it existed in Unix first edition.

ed /path/to/file
1,$s/^V^M$//
w
q

where ^V^M means typing Ctrl+V then Ctrl+M (to enter a literal line feed). If you know that all lines do end in CR LF, you can use 1,$s/.$// instead (indiscriminately remove the last character on each line).

How to remove Ctrl-M from files where dos2unix, perl, tr, and sed are not present?

2 Answers2

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