Replace using vim - Replace a pattern [...] by a string

Question

I have a file containing lines in below e.g. format -

[foo@host.com, bar@host.com], Payment processed - 23499, params = {'invoice':3243}

I only want the account numbers i.e. 23499. It's a number. Let's say it <account>. Its not a constant.

For that, I am trying to -

1. Remove params ...
2. Replace [...], from start of each line by whitespace

By ... I mean any string. I have tried -

# 1
:%s/params.*//g
# 2
:%s/\<[]\>//g
:%s/\<\[\]\>//g
:%s/\<[.*]\>//g
:%s/\<\[.*\]\>//g

All the things I have tried in # 2 have not worked. What am I doing wrong? How do I get <account>? Help me out.

Answer 1

You can use following sequence to only retain the account numbers (cudo's to J.D.Mohr)
note the space after the r in the command

:%norm $F,d$Bhv0r 

This assumes that there's only one , after the number you want to retain

Breakdown

:     -> Enter command mode
%norm -> Applies a normal command to the entire file
$     -> Jump to end of line
F,    -> Find preceding ,
d$    -> Delete until end of line
B     -> Jump back a word
hv0   -> Go left one character and select until beginning of line
r     -> replace selected text with <space>

Answer 2

To get only the <account> string

awk '{print $6}' file| sed 's/,//' >> newfile

For possible future usage of the main data, this could be useful

Answer 3

If you would look for <account> (something like <12345>) and have have < and > only in <account>, as it looked like in the original version of the question, then this could work:

%s/\v.*(\<.*\>).*/\1/

It matches < and > with anything between - which is in a group, and anything before and after in the line. That is replaced by just the group.

Answering the updated question:

If you do not have <account>, but a number in this place, with no < and >: this works in a similar way:

%s/\v.* - ([0-9]*), params =.*/\1/

It matches numbers, in a group to keep them. And it matches anything before that ends with " - ", and anything after that starts with , params =, both up to start or end of line.
So the expression matches the whole line, and is replaced by the matched group that contains the number.

It's using \v for "very magic" regular expressions see :help /magic.

Answer 4

As easy as it might be to want to use vim (or sed for this), awk is actually entirely capable of doing this type of matching and substitution all on its own:

$ awk '{ sub(/^.* - /, ""); sub(/,.*$/, ""); print $0 }' file
23499

The above matches everything (with awk's built-in sub() function) from the beginning of the line to the hyphen and space before the account number and replaces it with the empty string "". Then, it matches everything from the comma to the end of the line and replaces it with the empty string. This should robustly (e.g., regardless of how many emails or what their formatting might be) remove everything but the account number.

If you have access to gawk, then you can use a simpler solution (only one function call needed):

$ gawk 'match($0, /^.* - ([0-9]+),.*$/, a) { print a[1] }' file
23499

---

Of course, the above solutions print the new data to stdout. If you wanted to save the new data for use later, all you would need to do is add > newfile to the end of the above command (note, that > overwrites; if you would prefer appending, you can use >>).

awk has many limitations of its own (for example, working with many files at the same time), so it's not always the best tool for this type of manipulation. However, it is quite good at what it does, so when your use-case lines up with its round-house, I'd strongly recommend using it.

In addition, the above solution requires no interactive interface (like vim) and no piping.