the comma is separating different items and in each item I want to remove everything between - and : including - but keeping : HOw can I do that? so it should look like


I used sed 's/-.*://' 1.file > 2.file but ended up removing the whole file and just kept the first and last values.

  • 1
    It looks like your input is a single line, and sed operates a line at a time. Since your regular expression allows for matching .*, the longest (greedy) match is from the first - to the last :. That's why it's deleting everything. You could try replacing the .* with [^,]*, which will force it to stop at the comma between items. – Dave M. Sep 29 '17 at 20:51

.* is a greedy regexp, matching the longest possible match. You need to match the shortest match but match it globally on the whole line. Try

sed 's/-[^:-]*:/:/g' 1.file > 2.file

The character class [^:-] matches anything except colon and dash (and maybe it should match anything except colon only), so the regexp says "dash followed by any number of non-dash, non-colon characters followed by a colon". It then replaces that with a colon (since you wanted to keep that) and does the replacement globally (the trailing g) on the line. If you omit the g, only the first instance would be replaced.

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  • Thanks Nick, I still do not understand why cannot we say directly sed 's/-*:/:/g' why do we need [^:-]? – Ahmed Magdy Moustafa Sep 29 '17 at 21:26
  • .* will match the longest sequence of characters possible (that's why it's termed "greedy"). So /-.*:/ says "dash followed by any number of characters followed by colon": that matches the first dash and the last colon in your line (and everything in between) because that's longer than any other match. Is that clear? – NickD Sep 29 '17 at 21:30

Awk solution:

awk -F',' '{ for(i=1;i<=NF;i++) sub(/-[^:-]+/,"",$i) }1' OFS=',' 1.file

  • -F',' - field separator

  • for(i=1;i<=NF;i++) - iterating through all fields of the record

  • sub(/-[^:-]+/,"",$i - substitute the needed sequence (between - and : including - but keeping :)

The output:

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