CODEWITHSUNDEEP
unixawkcut
Archit Jain
Archit Jain

Reputation: 2234

How to get second last field from a cut command

I have a set of data as input and need the second last field based on deleimiter. The lines may have different numbers of delimiter. How can I get second last field ?

example input

text,blah,blaah,foo
this,is,another,text,line

expected output

blaah
text

Upvotes: 52

Views: 76630

Answers (6)

Chris Koknat
Chris Koknat

Reputation: 3451

Perl solution similar to awk solution from @iiSeymour

perl -lane 'print $F[-2]' file

These command-line options are used:

  • n loop around every line of the input file, do not automatically print every line

  • l removes newlines before processing, and adds them back in afterwards

  • a autosplit mode – split input lines into the @F array. Defaults to splitting on whitespace

  • e execute the perl code

The @F autosplit array starts at index [0] while awk fields start with $1
-1 is the last element
-2 is the second to last element

Upvotes: 4

arielf
arielf

Reputation: 5952

The most minimalist answer to this problem is to use my cuts utility:

$ cat file.txt
text,blah,blaah,foo
this,is,another,text,line

$ cuts -2 file.txt
blaah
text

cuts, which stands for "cut on steroids":

- automatically figures out the input field separators
- supports multi-char (and regexp) separators
- automatically pastes (side-by-side) multiple columns from multiple files
- supports negative offsets (from end of line)
- has good defaults to save typing + allows the user to override them

and much more.

I wrote cuts after being frustrated with the too many limitations of cut on Unix. It is designed to replace various cut/paste combos, slicing and dicing columns from multiple files, with multiple separator variations, while imposing minimal typing from the user.

You can get cuts (free software, Artistic Licence) from github: https://github.com/arielf/cuts/

Calling cuts without arguments will print a detailed Usage message.

Upvotes: 3

captcha
captcha

Reputation: 3756

Code for GNU :

$ echo text,blah,blaah,foo|sed -r 's/^(\S+,){2}(\S+),.*/\2/'
blaah

$ echo this,is,another,text,line|sed -r 's/^(\S+,){2}(\S+),.*/\2/'
text

Code example similar to sudo_O's awk code:

$ sed -r 's/.*,(\w+),\w+$/\1/' file
blaah
text

It might be better to use more specialised programs for CSV files, eg. or .

Upvotes: 2

Charles Duffy
Charles Duffy

Reputation: 295315

There's no need to use cut, rev, or any other tools external to bash here at all. Just read each line into an array, and pick out the piece you want:

while IFS=, read -r -a entries; do
  printf '%s\n' "${entries[${#entries[@]} - 2]}"
done <file

Doing this in pure bash is far faster than starting up a pipeline, at least for reasonably small inputs. For large inputs, the better tool is awk.

Upvotes: 6

Chris Seymour
Chris Seymour

Reputation: 85775

Awk is suited well for this:

awk -F, '{print $(NF-1)}' file

The variable NF is a special awk variable that contains the number of fields in the current record.

Upvotes: 46

Archit Jain
Archit Jain

Reputation: 2234

Got a hint from Unix cut except last two tokens and able to figure out the answer :

cat datafile | rev | cut -d '/' -f 2 | rev

Upvotes: 95

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