How do I swap the first two comma-separated fields on each line with one substitute command?

Explanation

When CSV-like data has two columns in the wrong order, manually fixing each line is slow and error-prone. A single substitution with capture groups can swap fields across the whole buffer instantly. This is a strong pattern for structured text refactors where delimiters are stable.

How it works

• :%s/.../.../ runs substitution on every line in the file
• \v enables very-magic regex mode for cleaner grouping syntax
• ^([^,]+),([^,]+), captures the first field as \1 and second as \2
• \2,\1, writes them back in reversed order while preserving the remainder of each line

Because the pattern anchors at line start and consumes only the first two comma-separated chunks, later columns are untouched.

Example

Before:

alpha,beta,gamma
one,two,three

Run:

:%s/\v^([^,]+),([^,]+),/\2,\1,/

After:

beta,alpha,gamma
two,one,three

Tips

• Add g only if your pattern can match more than once per line
• Use c (.../gc) when you want confirmation before each swap
• If fields can contain commas inside quotes, switch to a CSV-aware tool instead of regex