Manipulating text in first column only? [duplicate]

Question

Example Input:

[email protected] [email protected],[email protected]

Example Output:

[email protected] [email protected],[email protected]

So, in "normal" circumstances, it would obviously be easy to do something like:

sed 's/.com/.org/g'

But obviously in this case, I only want the suffix in the first column to be manipulated, I want the second column to be left untouched.

I don't mind what tool you propose to use. But I prefer it to available on a standard linux without needing further install (i.e. something like sed or awk or perl would be more preferable to bobsobscuretoolthatneedsinstalling).

Answer 1

If you just want to replace the first occurrence of .com with .org, all you need is the default behavior of sed's s/// operator. Just don't use the g flag:

$ sed 's/.com/.org/' file 
[email protected] [email protected],[email protected]

If you really want to only make the change on the first comma-defined field, so that if the first .com appears elsewhere in the line, it will remain unchanged, you can do something like:

$ perl -pe 's/^(\S+)\.com/$1.org/' file 
[email protected] [email protected],[email protected]

Or, safer in case com occurs as a substring (e.g. foo.common.net):

$ perl -pe 's/^(\S+)\.com\b/$1.org/' file 
[email protected] [email protected],[email protected]

Alternatively, in GNU sed:

$ sed -E 's/^(\S+)\.com\b/\1.org/' file 
[email protected] [email protected],[email protected]

Or, portably (assuming the first field is defined by the first space and not a tab or other whitespace):

$ sed -E 's/^([^ ])\.com /\1.org /' file 
[email protected] [email protected],[email protected]

Answer 2

$ awk '{ sub("\.com$", ".org", $1); print }' <file
[email protected] [email protected],[email protected]

This uses awk to substitute the text matched by \.com$ with .org in the first whitespace-delimited field (only) of each line. The output will be space-delimited.

Answer 3

You can do it using sed, just use a regexp that can only match the first word of the line:

sed -r 's/^(\S+)\.com(\s+)/\1.org\2/'

In slo-mo, change:

1. a sequence of one or more non-spaces from the beginning (^(\S+))
2. .com
3. a sequence of one or more non spaces (so that we can only match a final .com)

into:

1. the first sequence of non-spaces
2. .org
3. the sequence of spaces