Examples for various options and combinations are shown below. These will also act as a source for testing the rcut command.
Same as awk. Given newline as record separator, space and tab characters will be trimmed from the start/end of input lines. One or more space/tab characters will then act as the field separator.
Sample input file:
$ cat spaces.txt
1 2 3
x y z
i j k
$ cat -A spaces.txt
1 2^I3 $
x y z$
i j ^I^Ik^I$Here's some example operations with default field separators:
# format lines with single space between fields
# leading/trailing space/tab characters will be removed as well
# same as: awk '{$1=$1} 1' spaces.txt
$ rcut spaces.txt
1 2 3
x y z
i j k
# specific field
$ rcut -f2 spaces.txt
2
y
j
# multiple fields can be specified separated by , character
# unlike cut, order matters
$ rcut -f3,1 spaces.txt
3 1
z x
k i$ rcut -o: spaces.txt
1:2:3
x:y:z
i:j:k
$ rcut -o'{-}' spaces.txt
1{-}2{-}3
x{-}y{-}z
i{-}j{-}kHere's some examples with csv input:
$ cat scores.csv
Name,Maths,Physics,Chemistry
Ith,100,100,100
Cy,97,98,95
Lin,78,83,80
# single character input field separator
# implies same output field separator as well
$ rcut -d, -f1,4 scores.csv
Name,Chemistry
Ith,100
Cy,95
Lin,80
$ rcut -d, -o: -f4,2 scores.csv
Chemistry:Maths
100:100
95:97
80:78Input field separator can be multiple characters as well:
$ echo 'apple:-:fig:-:guava' | rcut -d:-: -f2
fig
# output field separator won't be same as input in this case
$ echo 'apple:-:fig:-:guava' | rcut -d:-: -f2,1
fig appleRange of fields can be specified separated by a - character. If negative indexing option -n is enabled (discussed later), the separator changes to : character.
$ printf '1 2 3 4 5\na b c d e\n' | rcut -f1-3
1 2 3
a b c
# multiple ranges can be specified, order matters
$ printf '1 2 3 4 5\na b c d e\n' | rcut -f2-3,5,1,2-4
2 3 5 1 2 3 4
b c e a b c dBeginning or ending or both can be ignored for a range.
# if - alone is used, it indicates all the fields
$ printf '1 2 3 4 5\na b c d e\n' | rcut -f-,1
1 2 3 4 5 1
a b c d e a
# if beginning of the range is left out, default is 1
$ rcut -f-2 spaces.txt
1 2
x y
i j
# if ending of the range is left out, default is last field of that line
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -f2- -o,
ball,cat
2,3,4,5Regular expression syntax will depend on the awk version.
$ echo 'apple : fig : guava' | rcut -d' *: *' -f2
fig
$ echo 'Sample123string42with777numbers' | rcut -d'[0-9]+' -f1,4
Sample numbers
# if you change mawk to gawk, you can also use rcut -d'\\W+'
$ echo 'load;err_msg--\ant,r2..not' | rcut -d'[^[:alnum:]_]+'
load err_msg ant r2 notUsing -F option will cause the content passed to -d option to be matched literally. If -o option isn't set, value passed to the -d option will be used.
$ echo '1\x5e2' | rcut -Fd'\x5e' -f1,2,1
1\x5e2\x5e1
$ echo 'a\b' | rcut -Fd'\' -f1,2,1
a\b\a
$ echo 'a\\b' | rcut -Fd'\\' -f1,2,1
a\\b\\a
$ echo '123)(%)*#^&(*@#.[](\\){1}\xyz' | rcut -Fd')(%)*#^&(*@#.[](\\){1}\' -f1
123
$ echo '123)(%)*#^&(*@#.[](\\){1}\xyz' | rcut -Fd')(%)*#^&(*@#.[](\\){1}\' -f2
xyz
# output should be same as input here
$ echo '123)(%)*#^&(*@#.[](\\){1}\xyz' | rcut -Fd')(%)*#^&(*@#.[](\\){1}\' -f1,2
123)(%)*#^&(*@#.[](\\){1}\xyz
# saner output with , as output delimiter
$ echo '123)(%)*#^&(*@#.[](\\){1}\xyz' | rcut -Fd')(%)*#^&(*@#.[](\\){1}\' -f1,2 -o,
123,xyzWhen -n option is used, you can specify -1 for last field, -2 for second-last field and so on. You'll have to use : character for ranges.
# last field
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -nf-1
cat
5
# last field and third-last field
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -nf-1,-3
cat apple
5 3
# first and last field
$ echo 'Sample123string42with777numbers' | rcut -d'[0-9]+' -nf1,-1
Sample numbers
# range separator is : when -n is active
# last four fields
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -nf-4:
apple ball cat
2 3 4 5The -c option will invert the field selections. Unlike the normal field extraction, order doesn't matter. All the fields except those specified by the -f option will be displayed using the same order as input.
# except second field
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -cf2
apple cat
1 3 4 5
# except first and third fields, order doesn't matter
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -cf3,1
ball
2 4 5
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -cf2-3
apple
1 4 5
# except last two fields
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -cnf-2:
apple
1 2 3
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -cnf-4
ball cat
1 3 4 5$ echo 'apple' | rcut -d '' -f2-4
p p l
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -o '' -f1,3
applecat
13The -s option behaves similarly to the -s option provided by cut. This will suppress a line from being printed if it doesn't contain the given IFS.
$ printf '1,2,3,4\nhello\na,b,c\n'
1,2,3,4
hello
a,b,c
$ printf '1,2,3,4\nhello\na,b,c\n' | rcut -d, -f2
2
hello
b
$ printf '1,2,3,4\nhello\na,b,c\n' | rcut -sd, -f2
2
b
$ printf '1,2,3,4\nhello\na,b,c\n' | rcut -csd, -f2
1,3,4
a,cUnicode processing might work for some cases depending on the current locale.
# single character input field separator
# so output field separator is also same as input separator
$ echo '1α2α3' | rcut -dα -f3,1,2
3α1α2
# input field separator is considered as multiple characters here
# so, output field separator will be space instead of α
$ echo '1α2α3' | LC_ALL=C rcut -dα -f3,1,2
3 1 2# mawk doesn't support {} form of quantifiers
# see https://unix.stackexchange.com/q/506119 for more details
$ echo '1aa2aa3' | rcut -d'a{2}' -f2
1aa2aa3
$ echo '1aa2aa3' | rcut -d'aa' -f2
2
# -g option will use gawk, which supports {} quantifiers
$ echo '1aa2aa3' | rcut -gd'a{2}' -f2
2Minimum field number is forced to be 1.
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -f0
apple
1
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -f0-0
apple
1
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -f1-0
apple
1
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -f22
cat
5
# first line has only three fields, so -4 becomes 1 (since minimum is 1)
# second line has five fields, so -4 becomes 2
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -nf-4,-1
apple cat
2 5
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -nf-100
apple
1
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -nf:-100
apple
1
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -nf-200:-100
apple
1
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -cnf-100
ball cat
2 3 4 5Maximum field number is forced to be the last field of that particular input line.
# no extra output field separator for first line even though it has only 3 fields
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -o, -f-4
apple,ball,cat
1,2,3,4
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -f4
cat
4
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -f100
cat
5Backslash as field delimiters.
$ echo 'a\b' | rcut -d'\' -f1,2,1
a\b\a
$ echo 'a,b' | rcut -d',' -o'\' -f1,2,1
a\b\a
$ echo 'a\b' | rcut -d'\' -o'\' -f1,2,1
a\b\a
# gawk needs special attention if -o is \
$ echo 'a,b' | rcut -d',' -go'\' -f1,2,1
a\b\aSpace between the option and empty string is mandatory. Otherwise, further options if any would become the argument.
# -f2-4 will get treated as argument for -d
$ echo 'apple' | rcut -d'' -f2-4
apple
$ echo 'apple' | rcut -d''
Option -d requires an argument.
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -o'' -f1,3
apple-f1,3ball-f1,3cat
1-f1,32-f1,33-f1,34-f1,35
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -o''
Option -o requires an argument.Bad arguments for -f option.
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -f1a
Field number can only use integer values
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -fx
Field number can only use integer values
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -f1.1
Field number can only use integer values
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -f ''
Field number can only use integer values
# can't use : if -n option isn't provided
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -f1:3
Field number can only use integer valuesInvalid options.
$ printf 'apple ball cat\n1 2 3 4 5' | rcut -t
Invalid option: -t
$ echo '123' | rcut -x
Invalid option: -x