Hopefully someone out there in the world can help me, and anyone else with a similar problem, find a simple solution to capturing data. I have spent hours trying a one liner to solve something I thought was a simple problem involving awk, a csv file, and saving the output as a bash variable. In short here's the nut...
The Missions:
1) To output every other column, starting from the LAST COLUMN, with a specific iteration count.
2) To output every other column, starting from NEXT TO LAST COLUMN, with a specific iteration count.
The Data (file.csv):
#12#SayWhat#2#4#2.25#3#1.5#1#1#1#3.25
#7#Smarty#9#6#5.25#5#4#4#3#2#3.25
#4#IfYouLike#4#1#.2#1#.5#2#1#3#3.75
#3#LaughingHard#8#8#13.75#8#13#6#8.5#4#6
#10#AtFunny#1#3#.2#2#.5#3#3#5#6.5
#8#PunchLines#7#7#10.25#7#10.5#8#11#6#12.75
Desired results for Mission 1:
2#2.25#1.5#1#3.25
9#5.25#4#3#3.25
4#.2#.5#1#3.75
8#13.75#13#8.5#6
1#.2#.5#3#6.5
7#10.25#10.5#11#12.75
Desired results for Mission 2:
SayWhat#4#3#1#1
Smarty#6#5#4#2
IfYouLike#1#1#2#3
LaughingHard#8#8#6#4
AtFunny#3#2#3#5
PunchLines#7#7#8#6
My Attempts:
The closes I have come to solving any of the above problems, is an ugly pipe (which is OK for skinning a cat) for Mission 1. However, it doesn't use any declared iterations (which should be 5). Also, I'm completely lost on solving Mission 2.
Any help to simplify the below and solving Mission 2 will be HELLA appreciated!
outcome=$( awk 'BEGIN {FS = "#"} {for (i = 0; i <= NF; i += 2) printf ("%s%c", $(NF-i), i + 2 <= NF ? "#" : "\n");}' file.csv | sed 's/##.*//g' | awk -F# '{for (i=NF;i>0;i--){printf $i"#"};printf "\n"}' | sed 's/#$//g' | awk -F# '{$1="";print $0}' OFS=# | sed 's/^#//g' );
Also, if doing a loop for a specific number of iterations is helpful in solving this problem, then magic number is 5. Maybe a solution could be a for-loop that is counting from right to left and skipping every other column as 1 iteration, with the starting column declared as an awk variable (Just a thought I have no way of knowing how to do)
Thank you for looking over this problem.
There are certainly more elegant ways to do this, but I am not really an awk person:
Part 1:
awk -F# '{ x = ""; for (f = NF; f > (NF - 5 * 2); f -= 2) { x = x ? $f "#" x : $f ; } print x }' file.csv
Output:
2#2.25#1.5#1#3.25
9#5.25#4#3#3.25
4#.2#.5#1#3.75
8#13.75#13#8.5#6
1#.2#.5#3#6.5
7#10.25#10.5#11#12.75
Part 2:
awk -F# '{ x = ""; for (f = NF - 1; f > (NF - 5 * 2); f -= 2) { x = x ? $f "#" x : $f ; } print x }' file.csv
Output:
SayWhat#4#3#1#1
Smarty#6#5#4#2
IfYouLike#1#1#2#3
LaughingHard#8#8#6#4
AtFunny#3#2#3#5
PunchLines#7#7#8#6
The literal 5 in each of those is your "number of iterations."
Sample data:
$ cat mission.dat
#12#SayWhat#2#4#2.25#3#1.5#1#1#1#3.25
#7#Smarty#9#6#5.25#5#4#4#3#2#3.25
#4#IfYouLike#4#1#.2#1#.5#2#1#3#3.75
#3#LaughingHard#8#8#13.75#8#13#6#8.5#4#6
#10#AtFunny#1#3#.2#2#.5#3#3#5#6.5
#8#PunchLines#7#7#10.25#7#10.5#8#11#6#12.75
One awk solution:
NOTE: OP can add logic to validate the input parameters.
$ cat mission
#!/bin/bash
# format: mission { 1 | 2 } { number_of_fields_to_display }
mission=${1} # assumes user inputs "1" or "2"
offset=$(( mission - 1 )) # subtract one to determine awk/NF offset
iteration_count=${2} # assume for now this is a positive integer
awk -F"#" -v offset=${offset} -v itcnt=${iteration_count} 'BEGIN { OFS=FS }
{ # we will start by counting fields backwards until we run out of fields
# or we hit "itcnt==iteration_count" fields
loopcnt=0
for (i=NF-offset ; i>=0; i-=2) # offset=0 for mission=1; offset=1 for mission=2
{ loopcnt++
if (loopcnt > itcnt)
break
fstart=i # keep track of the field we want to start with
}
# now printing our fields starting with field # "fstart";
# prefix the first printf with a empty string, then each successive
# field is prefixed with OFS=#
pfx = ""
for (i=fstart; i<= NF-offset; i+=2)
{ printf "%s%s",pfx,$i
pfx=OFS
}
# terminate a line of output with a linefeed
printf "\n"
}
' mission.dat
Some test runs:
###### mission #1
# with offset/iteration = 4
$ mission 1 4
2.25#1.5#1#3.25
5.25#4#3#3.25
.2#.5#1#3.75
13.75#13#8.5#6
.2#.5#3#6.5
10.25#10.5#11#12.75
#with offset/iteration = 5
$ mission 1 5
2#2.25#1.5#1#3.25
9#5.25#4#3#3.25
4#.2#.5#1#3.75
8#13.75#13#8.5#6
1#.2#.5#3#6.5
7#10.25#10.5#11#12.75
# with offset/iteration = 6
$ mission 1 6
12#2#2.25#1.5#1#3.25
7#9#5.25#4#3#3.25
4#4#.2#.5#1#3.75
3#8#13.75#13#8.5#6
10#1#.2#.5#3#6.5
8#7#10.25#10.5#11#12.75
###### mission #2
# with offset/iteration = 4
$ mission 2 4
4#3#1#1
6#5#4#2
1#1#2#3
8#8#6#4
3#2#3#5
7#7#8#6
# with offset/iteration = 5
$ mission 2 5
SayWhat#4#3#1#1
Smarty#6#5#4#2
IfYouLike#1#1#2#3
LaughingHard#8#8#6#4
AtFunny#3#2#3#5
PunchLines#7#7#8#6
# with offset/iteration = 6;
# notice we pick up field #1 = empty string so output starts with a '#'
$ mission 2 6
#SayWhat#4#3#1#1
#Smarty#6#5#4#2
#IfYouLike#1#1#2#3
#LaughingHard#8#8#6#4
#AtFunny#3#2#3#5
#PunchLines#7#7#8#6
this is probably not what you're asking but perhaps will give you an idea.
$ awk -F_ -v skip=4 -v endoff=0 '
BEGIN {OFS=FS}
{offset=(NF-endoff)%skip;
for(i=offset;i<=NF-endoff;i+=skip) printf "%s",$i (i>=(NF-endoff)?ORS:OFS)}' file
112_116_120
122_126_130
132_136_140
142_146_150
you specify the number of skips between columns and the end offset as input variables. Here, for last column end offset is set to zero and skip column is 4.
For clarity I used the input file
$ cat file
_111_112_113_114_115_116_117_118_119_120
_121_122_123_124_125_126_127_128_129_130
_131_132_133_134_135_136_137_138_139_140
_141_142_143_144_145_146_147_148_149_150
changing FS for your format should work.
Sample input data:
Col1, Col2
120000,1261
120000,119879
120000,117737
120000,14051
200000,58411
200000,115292
300000,279892
120000,98572
250000,249598
120000,14051
......
I used Excel with follow steps:
Col3=Col2/Col1.
Format Col3 with percentage
Use countif to group by Col3
How to do this task with awk or other way in linux command line ?
Expected result:
percent|count
0-20% | 10
21-50% | 5
51-100%| 10
I calculated the percent but i'm still finding the way to group by Col3
cat input.txt |awk -F"," '$3=100*$2/$1'
awk approach:
awk 'BEGIN {
FS=",";
OFS="|";
}
(NR > 1){
percent = 100 * $2 / $1;
if (percent <= 20) {
a["0-20%"] += 1;
} else if (percent <= 50) {
a2 += 1;
a["21-50%"] += 1;
} else {
a["51-100%"] += 1;
}
}
END {
print "percent", "count"
for (i in a) {
print i, a[i];
}
}' data
Sample output:
percent|count
0-20%|3
21-50%|1
51-100%|6
A generic self documented. Need some fine tuning depending on group name in result (due to +1% or not but not the real purpose)
awk -F ',' -v Step='0|20|50|100' '
BEGIN {
# define group
Gn = split( Step, aEdge, "|")
}
NR>1{
# Define wich percent
L = $2 * 100 / ($1>0 ? $1 : 1)
# in which group
for( j=1; ( L < aEdge[j] || L >= aEdge[j+1] ) && j < Gn;) j++
# add to group
G[j]++
}
# print result ordered
END {
print "percent|count"
for( i=1;i<Gn;i++) printf( "%d-%d%%|%d\n", aEdge[i], aEdge[i+1], G[i])
}
' data
another awk with parametric bins and formatted output.
$ awk -F, -v OFS=\| -v bins='20,50,100' '
BEGIN {n=split(bins,b)}
NR>1 {for(i=1;i<=n;i++)
if($2/$1 <= b[i]/100)
{a[b[i]]++; next}}
END {print "percent","count";
b[0]=-1;
for(i=1;i<=n;i++)
printf "%-7s|%3s\n", b[i-1]+1"-"b[i]"%",a[b[i]]}' file
percent|count
0-20% | 3
21-50% | 1
51-100%| 6
Pure bash:
# arguments are histogram boundaries *in ascending order*
hist () {
local lower=0$(printf '+(val*100>sum*%d)' "$#") val sum count n;
set -- 0 "$#" 100;
read -r
printf '%7s|%5s\n' percent count;
while IFS=, read -r sum val; do echo $((lower)); done |
sort -n | uniq -c |
while read count n; do
printf '%2d-%3d%%|%5d\n' "${#:n+1:2}" $count;
done
}
Example:
$ hist 20 50 < csv.dat
percent|count
0- 20%| 3
20- 50%| 1
50-100%| 6
Potential Issue: Does not print intervals with no values:
$ hist 20 25 45 50 < csv.dat
percent|count
0- 20%| 3
25- 45%| 1
50-100%| 6
Explanation:
lower is set to an expression which will count the number of percentages less than 100*val/num
The list of intervals is augmented with 0 and 100 so that the limits print correctly
The header line is ignored
The output header is printed
For each csv row, read the variables $num and $val and send the numeric evaluation of $lower (which uses those variables) to...
count the number of instances of each interval count...
and print the interval and count
Another, in GNU awk, using switch and regex to identify the values (since parsing was tagged in OP):
NR>1{
switch(p=$2/$1){
case /0\.[01][0-9]|\.20/:
a["0-20%"]++;
break;
case /\.[2-4][0-9]|\.50/:
a["21-50%"]++;
break;
default:
a["51-100%"]++
}
}
END{ for(i in a)print i, a[i] }
Run it:
$ awk -F, -f program.awk file
21-50% 1
0-20% 3
51-100% 6
how can I split a single column in several column of fixed dimension, for example I have a column like this:
1
2
3
4
5
6
7
8
and for size p. ex 4, I want to obtain
1 5
2 6
3 7
4 8
or for size p. ex 2, I want to obtain
1 3 5 7
2 4 6 8
Using awk:
awk '
BEGIN {
# Numbers of rows to print
n=4;
}
{
# Add to array with key = 0, 1, 2, 3, 0, 1, 2, ..
l[(NR-1)%n] = l[(NR-1)%n] " " $0
};
END {
# print the array
for (i = 0; i < length(l); i++) {
print l[i];
}
}
' file
OK, this is a bit long winded and not infallible but the following should work:
td=$( mktemp -d ); split -l <rows> <file> ${td}/x ; paste $( ls -1t ${td}/x* ) ; rm -rf ${td}; unset td
Where <cols> is the number of rows you want and file is your input file.
Explanation:
td=$( mktemp -d )
Creates a temporary directory so that we can put temporary files into it. Store this in td - it's possible that your shell has a td variable already but if you sub-shell for this your scope should be OK.
split -l <rows> <file> f ${td}/x
Split the original file into many smaller file, each <rows> long. These will be put into your temp directory and all files will be prefixed with x
paste $( ls -1t ${td}/x* )
Write these files out so that the lines in consecutive columns
rm -rf ${td}
Remove the files and directory.
unset td
Clean the environment.
Assuming you know the number of rows in your column (here, 8):
n=8
# to get output with 4 rows:
seq $n | pr -ts" " -$((n/4))
1 5
2 6
3 7
4 8
# to get output with 2 rows:
seq $n | pr -ts" " -$((n/2))
1 3 5 7
2 4 6 8
If you know the desired output width you can use column.
# Display in columns for an 80 column display
cat file | column -c 80
$ cat tst.awk
{ a[NR] = $0 }
END {
OFS=","
numRows = (numRows ? numRows : 1)
numCols = ceil(NR / numRows)
for ( rowNr=1; rowNr<=numRows; rowNr++ ) {
for ( colNr=1; colNr<=numCols; colNr++ ) {
idx = rowNr + ( (colNr - 1) * numRows )
printf "%s%s", a[idx], (colNr<numCols ? OFS : ORS)
}
}
}
function ceil(x, y){y=int(x); return(x>y?y+1:y)}
$ awk -v numRows=2 -f tst.awk file
1,3,5,7
2,4,6,8
$ awk -v numRows=4 -f tst.awk file
1,5
2,6
3,7
4,8
Note that above produces a CSV with the same number of fields in every row even when the number of input rows isn't an exact multiple of the desired number of output rows:
$ seq 10 | awk -v numRows=4 -f tst.awk
1,5,9
2,6,10
3,7,
4,8,
See https://stackoverflow.com/a/56725452/1745001 for how to do the opposite, i.e. generate a number of rows given a specified number of columns.
This line worked until I had whitespace in the second field.
svn status | grep '\!' | gawk '{print $2;}' > removedProjs
is there a way to have awk print everything in $2 or greater? ($3, $4.. until we don't have anymore columns?)
I suppose I should add that I'm doing this in a Windows environment with Cygwin.
Print all columns:
awk '{print $0}' somefile
Print all but the first column:
awk '{$1=""; print $0}' somefile
Print all but the first two columns:
awk '{$1=$2=""; print $0}' somefile
There's a duplicate question with a simpler answer using cut:
svn status | grep '\!' | cut -d\ -f2-
-d specifies the delimeter (space), -f specifies the list of columns (all starting with the 2nd)
You could use a for-loop to loop through printing fields $2 through $NF (built-in variable that represents the number of fields on the line).
Edit:
Since "print" appends a newline, you'll want to buffer the results:
awk '{out = ""; for (i = 2; i <= NF; i++) {out = out " " $i}; print out}'
Alternatively, use printf:
awk '{for (i = 2; i <= NF; i++) {printf "%s ", $i}; printf "\n"}'
awk '{out=$2; for(i=3;i<=NF;i++){out=out" "$i}; print out}'
My answer is based on the one of VeeArr, but I noticed it started with a white space before it would print the second column (and the rest). As I only have 1 reputation point, I can't comment on it, so here it goes as a new answer:
start with "out" as the second column and then add all the other columns (if they exist). This goes well as long as there is a second column.
Most solutions with awk leave an space. The options here avoid that problem.
Option 1
A simple cut solution (works only with single delimiters):
command | cut -d' ' -f3-
Option 2
Forcing an awk re-calc sometimes remove the added leading space (OFS) left by removing the first fields (works with some versions of awk):
command | awk '{ $1=$2="";$0=$0;} NF=NF'
Option 3
Printing each field formatted with printf will give more control:
$ in=' 1 2 3 4 5 6 7 8 '
$ echo "$in"|awk -v n=2 '{ for(i=n+1;i<=NF;i++) printf("%s%s",$i,i==NF?RS:OFS);}'
3 4 5 6 7 8
However, all previous answers change all repeated FS between fields to OFS. Let's build a couple of option that do not do that.
Option 4 (recommended)
A loop with sub to remove fields and delimiters at the front.
And using the value of FS instead of space (which could be changed).
Is more portable, and doesn't trigger a change of FS to OFS:
NOTE: The ^[FS]* is to accept an input with leading spaces.
$ in=' 1 2 3 4 5 6 7 8 '
$ echo "$in" | awk '{ n=2; a="^["FS"]*[^"FS"]+["FS"]+";
for(i=1;i<=n;i++) sub( a , "" , $0 ) } 1 '
3 4 5 6 7 8
Option 5
It is quite possible to build a solution that does not add extra (leading or trailing) whitespace, and preserve existing whitespace(s) using the function gensub from GNU awk, as this:
$ echo ' 1 2 3 4 5 6 7 8 ' |
awk -v n=2 'BEGIN{ a="^["FS"]*"; b="([^"FS"]+["FS"]+)"; c="{"n"}"; }
{ print(gensub(a""b""c,"",1)); }'
3 4 5 6 7 8
It also may be used to swap a group of fields given a count n:
$ echo ' 1 2 3 4 5 6 7 8 ' |
awk -v n=2 'BEGIN{ a="^["FS"]*"; b="([^"FS"]+["FS"]+)"; c="{"n"}"; }
{
d=gensub(a""b""c,"",1);
e=gensub("^(.*)"d,"\\1",1,$0);
print("|"d"|","!"e"!");
}'
|3 4 5 6 7 8 | ! 1 2 !
Of course, in such case, the OFS is used to separate both parts of the line, and the trailing white space of the fields is still printed.
NOTE: [FS]* is used to allow leading spaces in the input line.
I personally tried all the answers mentioned above, but most of them were a bit complex or just not right. The easiest way to do it from my point of view is:
awk -F" " '{ for (i=4; i<=NF; i++) print $i }'
Where -F" " defines the delimiter for awk to use. In my case is the whitespace, which is also the default delimiter for awk. This means that -F" " can be ignored.
Where NF defines the total number of fields/columns. Therefore the loop will begin from the 4th field up to the last field/column.
Where $N retrieves the value of the Nth field. Therefore print $i will print the current field/column based based on the loop count.
awk '{ for(i=3; i<=NF; ++i) printf $i""FS; print "" }'
lauhub proposed this correct, simple and fast solution here
This was irritating me so much, I sat down and wrote a cut-like field specification parser, tested with GNU Awk 3.1.7.
First, create a new Awk library script called pfcut, with e.g.
sudo nano /usr/share/awk/pfcut
Then, paste in the script below, and save. After that, this is how the usage looks like:
$ echo "t1 t2 t3 t4 t5 t6 t7" | awk -f pfcut --source '/^/ { pfcut("-4"); }'
t1 t2 t3 t4
$ echo "t1 t2 t3 t4 t5 t6 t7" | awk -f pfcut --source '/^/ { pfcut("2-"); }'
t2 t3 t4 t5 t6 t7
$ echo "t1 t2 t3 t4 t5 t6 t7" | awk -f pfcut --source '/^/ { pfcut("-2,4,6-"); }'
t1 t2 t4 t6 t7
To avoid typing all that, I guess the best one can do (see otherwise Automatically load a user function at startup with awk? - Unix & Linux Stack Exchange) is add an alias to ~/.bashrc; e.g. with:
$ echo "alias awk-pfcut='awk -f pfcut --source'" >> ~/.bashrc
$ source ~/.bashrc # refresh bash aliases
... then you can just call:
$ echo "t1 t2 t3 t4 t5 t6 t7" | awk-pfcut '/^/ { pfcut("-2,4,6-"); }'
t1 t2 t4 t6 t7
Here is the source of the pfcut script:
# pfcut - print fields like cut
#
# sdaau, GNU GPL
# Nov, 2013
function spfcut(formatstring)
{
# parse format string
numsplitscomma = split(formatstring, fsa, ",");
numspecparts = 0;
split("", parts); # clear/initialize array (for e.g. `tail` piping into `awk`)
for(i=1;i<=numsplitscomma;i++) {
commapart=fsa[i];
numsplitsminus = split(fsa[i], cpa, "-");
# assume here a range is always just two parts: "a-b"
# also assume user has already sorted the ranges
#print numsplitsminus, cpa[1], cpa[2]; # debug
if(numsplitsminus==2) {
if ((cpa[1]) == "") cpa[1] = 1;
if ((cpa[2]) == "") cpa[2] = NF;
for(j=cpa[1];j<=cpa[2];j++) {
parts[numspecparts++] = j;
}
} else parts[numspecparts++] = commapart;
}
n=asort(parts); outs="";
for(i=1;i<=n;i++) {
outs = outs sprintf("%s%s", $parts[i], (i==n)?"":OFS);
#print(i, parts[i]); # debug
}
return outs;
}
function pfcut(formatstring) {
print spfcut(formatstring);
}
Would this work?
awk '{print substr($0,length($1)+1);}' < file
It leaves some whitespace in front though.
Printing out columns starting from #2 (the output will have no trailing space in the beginning):
ls -l | awk '{sub(/[^ ]+ /, ""); print $0}'
echo "1 2 3 4 5 6" | awk '{ $NF = ""; print $0}'
this one uses awk to print all except the last field
This is what I preferred from all the recommendations:
Printing from the 6th to last column.
ls -lthr | awk '{out=$6; for(i=7;i<=NF;i++){out=out" "$i}; print out}'
or
ls -lthr | awk '{ORS=" "; for(i=6;i<=NF;i++) print $i;print "\n"}'
If you need specific columns printed with arbitrary delimeter:
awk '{print $3 " " $4}'
col#3 col#4
awk '{print $3 "anything" $4}'
col#3anythingcol#4
So if you have whitespace in a column it will be two columns, but you can connect it with any delimiter or without it.
Perl solution:
perl -lane 'splice #F,0,1; print join " ",#F' 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
splice #F,0,1 cleanly removes column 0 from the #F array
join " ",#F joins the elements of the #F array, using a space in-between each element
Python solution:
python -c "import sys;[sys.stdout.write(' '.join(line.split()[1:]) + '\n') for line in sys.stdin]" < file
I want to extend the proposed answers to the situation where fields are delimited by possibly several whitespaces –the reason why the OP is not using cut I suppose.
I know the OP asked about awk, but a sed approach would work here (example with printing columns from the 5th to the last):
pure sed approach
sed -r 's/^\s*(\S+\s+){4}//' somefile
Explanation:
s/// is the standard command to perform substitution
^\s* matches any consecutive whitespace at the beginning of the line
\S+\s+ means a column of data (non-whitespace chars followed by whitespace chars)
(){4} means the pattern is repeated 4 times.
sed and cut
sed -r 's/^\s+//; s/\s+/\t/g' somefile | cut -f5-
by just replacing consecutive whitespaces by a single tab;
tr and cut:
tr can also be used to squeeze consecutive characters with the -s option.
tr -s [:blank:] <somefile | cut -d' ' -f5-
If you don't want to reformat the part of the line that you don't chop off, the best solution I can think of is written in my answer in:
How to print all the columns after a particular number using awk?
It chops what is before the given field number N, and prints all the rest of the line, including field number N and maintaining the original spacing (it does not reformat). It doesn't mater if the string of the field appears also somewhere else in the line.
Define a function:
fromField () {
awk -v m="\x01" -v N="$1" '{$N=m$N; print substr($0,index($0,m)+1)}'
}
And use it like this:
$ echo " bat bi iru lau bost " | fromField 3
iru lau bost
$ echo " bat bi iru lau bost " | fromField 2
bi iru lau bost
Output maintains everything, including trailing spaces
In you particular case:
svn status | grep '\!' | fromField 2 > removedProjs
If your file/stream does not contain new-line characters in the middle of the lines (you could be using a different Record Separator), you can use:
awk -v m="\x0a" -v N="3" '{$N=m$N ;print substr($0, index($0,m)+1)}'
The first case will fail only in files/streams that contain the rare hexadecimal char number 1
This awk function returns substring of $0 that includes fields from begin to end:
function fields(begin, end, b, e, p, i) {
b = 0; e = 0; p = 0;
for (i = 1; i <= NF; ++i) {
if (begin == i) { b = p; }
p += length($i);
e = p;
if (end == i) { break; }
p += length(FS);
}
return substr($0, b + 1, e - b);
}
To get everything starting from field 3:
tail = fields(3);
To get section of $0 that covers fields 3 to 5:
middle = fields(3, 5);
b, e, p, i nonsense in function parameter list is just an awk way of declaring local variables.
All of the other answers given here and in linked questions fail in various ways given various possible FS values. Some leave leading and/or trailing white space, some convert every FS to the OFS, some rely on semantics that only apply when FS is the default value, some rely on negating FS in a bracket expression which will fail given a multi-char FS, etc.
To do this robustly for any FS, use GNU awk for the 4th arg to split():
$ cat tst.awk
{
split($0,flds,FS,seps)
for ( i=n; i<=NF; i++ ) {
printf "%s%s", flds[i], seps[i]
}
print ""
}
$ printf 'a b c d\n' | awk -v n=3 -f tst.awk
c d
$ printf ' a b c d\n' | awk -v n=3 -f tst.awk
c d
$ printf ' a b c d\n' | awk -v n=3 -F'[ ]' -f tst.awk
b c d
$ printf ' a b c d\n' | awk -v n=3 -F'[ ]+' -f tst.awk
b c d
$ printf 'a###b###c###d\n' | awk -v n=3 -F'###' -f tst.awk
c###d
$ printf '###a###b###c###d\n' | awk -v n=3 -F'###' -f tst.awk
b###c###d
Note that I'm using split() above because it's 3rg arg is a field separator, not just a regexp like the 2nd arg to match(). The difference is that field separators have additional semantics to regexps such as skipping leading and/or trailing blanks when the separator is a single blank char - if you wanted to use a while(match()) loop or any form of *sub() to emulate the above then you'd need to write code to implement those semantics whereas split() already implements them for you.
Awk examples looks complex here, here is simple Bash shell syntax:
command | while read -a cols; do echo ${cols[#]:1}; done
Where 1 is your nth column counting from 0.
Example
Given this content of file (in.txt):
c1
c1 c2
c1 c2 c3
c1 c2 c3 c4
c1 c2 c3 c4 c5
here is the output:
$ while read -a cols; do echo ${cols[#]:1}; done < in.txt
c2
c2 c3
c2 c3 c4
c2 c3 c4 c5
This would work if you are using Bash and you could use as many 'x ' as elements you wish to discard and it ignores multiple spaces if they are not escaped.
while read x b; do echo "$b"; done < filename
Perl:
#m=`ls -ltr dir | grep ^d | awk '{print \$6,\$7,\$8,\$9}'`;
foreach $i (#m)
{
print "$i\n";
}
UPDATE :
if you wanna use no function calls at all while preserving the spaces and tabs in between the remaining fields, then do :
echo " 1 2 33 4444 555555 \t6666666 " |
{m,g}awk ++NF FS='^[ \t]*[^ \t]*[ \t]+|[ \t]+$' OFS=
=
2 33 4444 555555 6666666
===================
You can make it a lot more straight forward :
svn status | [m/g]awk '/!/*sub("^[^ \t]*[ \t]+",_)'
svn status | [n]awk '(/!/)*sub("^[^ \t]*[ \t]+",_)'
Automatically takes care of the grep earlier in the pipe, as well as trimming out extra FS after blanking out $1, with the added bonus of leaving rest of the original input untouched instead of having tabs overwritten with spaces (unless that's the desired effect)
If you're very certain $1 does not contain special characters that need regex escaping, then it's even easier :
mawk '/!/*sub($!_"[ \t]+",_)'
gawk -c/P/e '/!/*sub($!_"""[ \t]+",_)'
Or if you prefer customizing FS+OFS to handle it all :
mawk 'NF*=/!/' FS='^[^ \t]*[ \t]+' OFS='' # this version uses OFS
This should be a reasonably comprehensive awk-field-sub-string-extraction function that
returns substring of $0 based on input ranges, inclusive
clamp in out of range values,
handle variable length field SEPs
has speedup treatments for ::
completely no inputs, returning $0 directly
input values resulting in guaranteed empty string ("")
FROM-field == 1
FS = "" that has split $0 out by individual chars
(so the FROM <(_)> and TO <(__)> fields behave like cut -c rather than cut -f)
original $0 restored, w/o overwriting FS seps with OFS
|
{m,g}awk '{
2 print "\n|---BEFORE-------------------------\n"
3 ($0) "\n|----------------------------\n\n ["
4 fld2(2, 5) "]\n [" fld2(3) "]\n [" fld2(4, 2)
5 "]<----------------------------------------------should be
6 empty\n [" fld2(3, 11) "]<------------------------should be
7 capped by NF\n [" fld2() "]\n [" fld2((OFS=FS="")*($0=$0)+11,
8 23) "]<-------------------FS=\"\", split by chars
9 \n\n|---AFTER-------------------------\n" ($0)
10 "\n|----------------------------"
11 }
12 function fld2(_,__,___,____,_____)
13 {
if (+__==(_=-_<+_ ?+_:_<_) || (___=____="")==__ || !NF) {
return $_
16 } else if (NF<_ || (__=NF<+__?NF:+__)<(_=+_?_:!_)) {
return ___
18 } else if (___==FS || _==!___) {
19 return ___<FS \
? substr("",$!_=$!_ substr("",__=$!(NF=__)))__
20 : substr($(_<_),_,__)
21 }
22 _____=$+(____=___="\37\36\35\32\31\30\27\26\25"\
"\24\23\21\20\17\16\6\5\4\3\2\1")
23 NF=__
24 if ($(!_)~("["(___)"]")) {
25 gsub("..","\\&&",___) + gsub(".",___,____)
27 ___=____
28 }
29 __=(_) substr("",_+=_^=_<_)
30 while(___!="") {
31 if ($(!_)!~(____=substr(___,--_,++_))) {
32 ___=____
33 break }
35 ___=substr(___,_+_^(!_))
36 }
37 return \
substr("",($__=___ $__)==(__=substr($!_,
_+index($!_,___))),_*($!_=_____))(__)
}'
those <TAB> are actual \t \011 but relabeled for display clarity
|---BEFORE-------------------------
1 2 33 4444 555555 <TAB>6666666
|----------------------------
[2 33 4444 555555]
[33]
[]<---------------------------------------------- should be empty
[33 4444 555555 6666666]<------------------------ should be capped by NF
[ 1 2 33 4444 555555 <TAB>6666666 ]
[ 2 33 4444 555555 <TAB>66]<------------------- FS="", split by chars
|---AFTER-------------------------
1 2 33 4444 555555 <TAB>6666666
|----------------------------
I wasn't happy with any of the awk solutions presented here because I wanted to extract the first few columns and then print the rest, so I turned to perl instead. The following code extracts the first two columns, and displays the rest as is:
echo -e "a b c d\te\t\tf g" | \
perl -ne 'my #f = split /\s+/, $_, 3; printf "first: %s second: %s rest: %s", #f;'
The advantage compared to the perl solution from Chris Koknat is that really only the first n elements are split off from the input string; the rest of the string isn't split at all and therefor stays completely intact. My example demonstrates this with a mix of spaces and tabs.
To change the amount of columns that should be extracted, replace the 3 in the example with n+1.
ls -la | awk '{o=$1" "$3; for (i=5; i<=NF; i++) o=o" "$i; print o }'
from this answer is not bad but the natural spacing is gone.
Please then compare it to this one:
ls -la | cut -d\ -f4-
Then you'd see the difference.
Even ls -la | awk '{$1=$2=""; print}' which is based on the answer voted best thus far is not preserve the formatting.
Thus I would use the following, and it also allows explicit selective columns in the beginning:
ls -la | cut -d\ -f1,4-
Note that every space counts for columns too, so for instance in the below, columns 1 and 3 are empty, 2 is INFO and 4 is:
$ echo " INFO 2014-10-11 10:16:19 main " | cut -d\ -f1,3
$ echo " INFO 2014-10-11 10:16:19 main " | cut -d\ -f2,4
INFO 2014-10-11
$
If you want formatted text, chain your commands with echo and use $0 to print the last field.
Example:
for i in {8..11}; do
s1="$i"
s2="str$i"
s3="str with spaces $i"
echo -n "$s1 $s2" | awk '{printf "|%3d|%6s",$1,$2}'
echo -en "$s3" | awk '{printf "|%-19s|\n", $0}'
done
Prints:
| 8| str8|str with spaces 8 |
| 9| str9|str with spaces 9 |
| 10| str10|str with spaces 10 |
| 11| str11|str with spaces 11 |
The top-voted answer by zed_0xff did not work for me.
I have a log where after $5 with an IP address can be more text or no text. I need everything from the IP address to the end of the line should there be anything after $5. In my case, this is actually within an awk program, not an awk one-liner so awk must solve the problem. When I try to remove the first 4 fields using the solution proposed by zed_0xff:
echo " 7 27.10.16. Thu 11:57:18 37.244.182.218" | awk '{$1=$2=$3=$4=""; printf "[%s]\n", $0}'
it spits out wrong and useless response (I added [..] to demonstrate):
[ 37.244.182.218 one two three]
There are even some suggestions to combine substr with this wrong answer, but that only complicates things. It offers no improvement.
Instead, if columns are fixed width until the cut point and awk is needed, the correct answer is:
echo " 7 27.10.16. Thu 11:57:18 37.244.182.218" | awk '{printf "[%s]\n", substr($0,28)}'
which produces the desired output:
[37.244.182.218 one two three]