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The main reason I use awk 90% of the time is that its field parsing algorithm does "the right thing" in most cases (i.e. divide fields by 1 or more whitespace c

The main reason I use awk 90% of the time is that its field parsing algorithm does "the right thing" in most cases (i.e. divide fields by 1 or more whitespace characters) without a lot of boilerplate, so it's really easy to throw into a pipeline.

cyphar 9y ago
That's what I was referencing when I said > Pulling out a field from a line is what most people use awk for, but it's honestly the least interesting part of awk. In fact, if cut supported regular expressions for specifying the field and record separators people wouldn't be using awk for that purpose (because that's all that $n does). There's nothing magical about awk's default FS. It's literally just /\s+/. If cut's -d was slightly more clever you wouldn't need to use awk.
- bewuethr 9y ago
  The default FS throws away leading blanks, though, which doesn't happen if you set it explicitly to \s+, so a tiny little bit of magic does go on after all.
  - cyphar 9y ago
    Fair enough, though ultimately you could emulate it with sed: some-cmd | sed -E '{ s/^\s+//g ; s/\s+/ /g }' | cut -f$n
- joosters 9y ago
  I wish the default 'cut' implementation could be just a little more clever - regex delimiters would be good, it doesn't even support multiple characters :( Also, cut's output manipulation is surprising. '-f 2,1' is actually the same as '-f 1,2' - you can't change the order of printing. I know there are other programs that can do the job, but it's a little frustrating when you can 'almost' get there with a chain of piped commands and a simple tool like cut, but have to fall back on a 'real' programming language to do just that extra bit of manipulation (awk, perl, whatever, and yes, I know the shell is a programming language but you get my point!)
  - cyphar 9y ago
    You mean to say you don't use some-cmd | sed -E 's/^\s+//;s/\s+/ /g' | cut -f$n Rather than some-cmd | awk '{ print $n }' ;) Also I agree it's silly you can't change the field order.
  - derriz 9y ago
    If you pipe your file through "while read f1 f2 f3 ; do echo field2 is $f2 ; done" for example you can pick out fields. Re-ordering them is just of a special case of any sort of bash manipulation you can do in the loop body. Admittedly for the very basic case, it's not as terse as "cut -f2" but if you're doing any further processing on the stream then I find it's often shorter.
    - vidarh 9y ago
      In bash you can also do do "while read -a F ; do echo field2 is ${F:1} ; done". (-a will assign each field to an zero indexed array)
    - fiddlerwoaroof 9y ago
      Yeah, I thought of mentioning this. The reason I don't do this, though, is that I generally dislike keeping track of when the shell does or does not automatically split input, so I only use `read` with the -r option.
kotokz 9y ago
perl can do the same with -alne parms. but indeed awk has been widely used due to having this by default.

cyphar 9y ago

That's what I was referencing when I said > Pulling out a field from a line is what most people use awk for, but it's honestly the least interesting part of awk. In fact, if cut supported regular expressions for specifying the field and record separators people wouldn't be using awk for that purpose (because that's all that $n does). There's nothing magical about awk's default FS. It's literally just /\s+/. If cut's -d was slightly more clever you wouldn't need to use awk.

bewuethr 9y ago
The default FS throws away leading blanks, though, which doesn't happen if you set it explicitly to \s+, so a tiny little bit of magic does go on after all.
- cyphar 9y ago
  Fair enough, though ultimately you could emulate it with sed: some-cmd | sed -E '{ s/^\s+//g ; s/\s+/ /g }' | cut -f$n
joosters 9y ago
I wish the default 'cut' implementation could be just a little more clever - regex delimiters would be good, it doesn't even support multiple characters :( Also, cut's output manipulation is surprising. '-f 2,1' is actually the same as '-f 1,2' - you can't change the order of printing. I know there are other programs that can do the job, but it's a little frustrating when you can 'almost' get there with a chain of piped commands and a simple tool like cut, but have to fall back on a 'real' programming language to do just that extra bit of manipulation (awk, perl, whatever, and yes, I know the shell is a programming language but you get my point!)
- cyphar 9y ago
  You mean to say you don't use some-cmd | sed -E 's/^\s+//;s/\s+/ /g' | cut -f$n Rather than some-cmd | awk '{ print $n }' ;) Also I agree it's silly you can't change the field order.
- derriz 9y ago
  If you pipe your file through "while read f1 f2 f3 ; do echo field2 is $f2 ; done" for example you can pick out fields. Re-ordering them is just of a special case of any sort of bash manipulation you can do in the loop body. Admittedly for the very basic case, it's not as terse as "cut -f2" but if you're doing any further processing on the stream then I find it's often shorter.
  - vidarh 9y ago
    In bash you can also do do "while read -a F ; do echo field2 is ${F:1} ; done". (-a will assign each field to an zero indexed array)
  - fiddlerwoaroof 9y ago
    Yeah, I thought of mentioning this. The reason I don't do this, though, is that I generally dislike keeping track of when the shell does or does not automatically split input, so I only use `read` with the -r option.

kotokz 9y ago

perl can do the same with -alne parms. but indeed awk has been widely used due to having this by default.