I would like to switch column 2 with 3 in a csv-file
cat test.csv
1,1;1,2;1,3
2,1;2,2;2,3
3,1;3,2;3,3
I tried it with:
awk '{FS=";"; OFS=";"} { col1=$1;col2=$2;col3=$3; print col1,col3,col2 }' test.csv
but it results in:
;;1;1,2;1,3
;2,22,3
;3,23,3
What am I doing wrong?
Following may help you on same.
awk -F";" '{print $1,$3,$2}' OFS=";" Input_file
OR
awk -F";" '{gsub(.\r/,"");print $1,$3,$2}' OFS=";" Input_file
In case your Input_file is having control M/carriage characters then use above code for same.
Related
I found some ways to pass external shell variables to an awk script, but I'm confused about ' and ".
First, I tried with a shell script:
$ v=123test
$ echo $v
123test
$ echo "$v"
123test
Then tried awk:
$ awk 'BEGIN{print "'$v'"}'
$ 123test
$ awk 'BEGIN{print '"$v"'}'
$ 123
Why is the difference?
Lastly I tried this:
$ awk 'BEGIN{print " '$v' "}'
$ 123test
$ awk 'BEGIN{print ' "$v" '}'
awk: cmd. line:1: BEGIN{print
awk: cmd. line:1: ^ unexpected newline or end of string
I'm confused about this.
#Getting shell variables into awk
may be done in several ways. Some are better than others. This should cover most of them. If you have a comment, please leave below. v1.5
Using -v (The best way, most portable)
Use the -v option: (P.S. use a space after -v or it will be less portable. E.g., awk -v var= not awk -vvar=)
variable="line one\nline two"
awk -v var="$variable" 'BEGIN {print var}'
line one
line two
This should be compatible with most awk, and the variable is available in the BEGIN block as well:
If you have multiple variables:
awk -v a="$var1" -v b="$var2" 'BEGIN {print a,b}'
Warning. As Ed Morton writes, escape sequences will be interpreted so \t becomes a real tab and not \t if that is what you search for. Can be solved by using ENVIRON[] or access it via ARGV[]
PS If you have vertical bar or other regexp meta characters as separator like |?( etc, they must be double escaped. Example 3 vertical bars ||| becomes -F'\\|\\|\\|'. You can also use -F"[|][|][|]".
Example on getting data from a program/function inn to awk (here date is used)
awk -v time="$(date +"%F %H:%M" -d '-1 minute')" 'BEGIN {print time}'
Example of testing the contents of a shell variable as a regexp:
awk -v var="$variable" '$0 ~ var{print "found it"}'
Variable after code block
Here we get the variable after the awk code. This will work fine as long as you do not need the variable in the BEGIN block:
variable="line one\nline two"
echo "input data" | awk '{print var}' var="${variable}"
or
awk '{print var}' var="${variable}" file
Adding multiple variables:
awk '{print a,b,$0}' a="$var1" b="$var2" file
In this way we can also set different Field Separator FS for each file.
awk 'some code' FS=',' file1.txt FS=';' file2.ext
Variable after the code block will not work for the BEGIN block:
echo "input data" | awk 'BEGIN {print var}' var="${variable}"
Here-string
Variable can also be added to awk using a here-string from shells that support them (including Bash):
awk '{print $0}' <<< "$variable"
test
This is the same as:
printf '%s' "$variable" | awk '{print $0}'
P.S. this treats the variable as a file input.
ENVIRON input
As TrueY writes, you can use the ENVIRON to print Environment Variables.
Setting a variable before running AWK, you can print it out like this:
X=MyVar
awk 'BEGIN{print ENVIRON["X"],ENVIRON["SHELL"]}'
MyVar /bin/bash
ARGV input
As Steven Penny writes, you can use ARGV to get the data into awk:
v="my data"
awk 'BEGIN {print ARGV[1]}' "$v"
my data
To get the data into the code itself, not just the BEGIN:
v="my data"
echo "test" | awk 'BEGIN{var=ARGV[1];ARGV[1]=""} {print var, $0}' "$v"
my data test
Variable within the code: USE WITH CAUTION
You can use a variable within the awk code, but it's messy and hard to read, and as Charles Duffy points out, this version may also be a victim of code injection. If someone adds bad stuff to the variable, it will be executed as part of the awk code.
This works by extracting the variable within the code, so it becomes a part of it.
If you want to make an awk that changes dynamically with use of variables, you can do it this way, but DO NOT use it for normal variables.
variable="line one\nline two"
awk 'BEGIN {print "'"$variable"'"}'
line one
line two
Here is an example of code injection:
variable='line one\nline two" ; for (i=1;i<=1000;++i) print i"'
awk 'BEGIN {print "'"$variable"'"}'
line one
line two
1
2
3
.
.
1000
You can add lots of commands to awk this way. Even make it crash with non valid commands.
One valid use of this approach, though, is when you want to pass a symbol to awk to be applied to some input, e.g. a simple calculator:
$ calc() { awk -v x="$1" -v z="$3" 'BEGIN{ print x '"$2"' z }'; }
$ calc 2.7 '+' 3.4
6.1
$ calc 2.7 '*' 3.4
9.18
There is no way to do that using an awk variable populated with the value of a shell variable, you NEED the shell variable to expand to become part of the text of the awk script before awk interprets it. (see comment below by Ed M.)
Extra info:
Use of double quote
It's always good to double quote variable "$variable"
If not, multiple lines will be added as a long single line.
Example:
var="Line one
This is line two"
echo $var
Line one This is line two
echo "$var"
Line one
This is line two
Other errors you can get without double quote:
variable="line one\nline two"
awk -v var=$variable 'BEGIN {print var}'
awk: cmd. line:1: one\nline
awk: cmd. line:1: ^ backslash not last character on line
awk: cmd. line:1: one\nline
awk: cmd. line:1: ^ syntax error
And with single quote, it does not expand the value of the variable:
awk -v var='$variable' 'BEGIN {print var}'
$variable
More info about AWK and variables
Read this faq.
It seems that the good-old ENVIRON awk built-in hash is not mentioned at all. An example of its usage:
$ X=Solaris awk 'BEGIN{print ENVIRON["X"], ENVIRON["TERM"]}'
Solaris rxvt
You could pass in the command-line option -v with a variable name (v) and a value (=) of the environment variable ("${v}"):
% awk -vv="${v}" 'BEGIN { print v }'
123test
Or to make it clearer (with far fewer vs):
% environment_variable=123test
% awk -vawk_variable="${environment_variable}" 'BEGIN { print awk_variable }'
123test
You can utilize ARGV:
v=123test
awk 'BEGIN {print ARGV[1]}' "$v"
Note that if you are going to continue into the body, you will need to adjust
ARGC:
awk 'BEGIN {ARGC--} {print ARGV[2], $0}' file "$v"
I just changed #Jotne's answer for "for loop".
for i in `seq 11 20`; do host myserver-$i | awk -v i="$i" '{print "myserver-"i" " $4}'; done
I had to insert date at the beginning of the lines of a log file and it's done like below:
DATE=$(date +"%Y-%m-%d")
awk '{ print "'"$DATE"'", $0; }' /path_to_log_file/log_file.log
It can be redirect to another file to save
Pro Tip
It could come handy to create a function that handles this so you dont have to type everything every time. Using the selected solution we get...
awk_switch_columns() {
cat < /dev/stdin | awk -v a="$1" -v b="$2" " { t = \$a; \$a = \$b; \$b = t; print; } "
}
And use it as...
echo 'a b c d' | awk_switch_columns 2 4
Output:
a d c b
I want to add a column at the multiple (500) CSV files (same dimensionality). Each column should act as an identifier for the individual file. I want to create a bash script using awk(I am a new bee in awk). The CSV files do come with headers.
For eg.
Input File1.csv
#name,#age,#height
A,12,4.5
B,13,5.0
Input File2.csv
#name,#age,#height
C,11,4.6
D,12,4.3
I want to add a new column "#ID" in both the files, where the value of ID will be same for an individual file but not for both the file.
Expected Output
File1.csv
#name,#age,#height,#ID
A,12,4.5,1
B,13,5.0,1
Expected File2.csv
#name,#age,#height,#ID
C,11,4.6,2
D,12,4.3,2
Please suggest.
If you don't need to extract the id number from the filename, this should do.
$ c=1; for f in File*.csv;
do
sed -i '1s/$/,#ID/; 2,$s/$/,'$c'/' "$f";
c=$((c+1));
done
note that this is inplace edit. Perhaps make a backup or test first.
UPDATE
If you don't need the individual files to be updated, this may work better for you
$ awk -v OFS=, 'BEGIN {f="allFiles.csv"}
FNR==1 {c++; print $0,"#ID" > f; next}
{print $0,c > f}' File*.csv
awk -F, -v OFS=, ‘
FNR == 1 {
$(NF + 1) = “ID#”
i++
f = FILENAME
sub(/Input/, “Output”, f)
} FNR != 1 {
$(NF + 1) = i
} {
print > f
}’ Input*.csv
With GNU awk for inplace editing and ARGIND:
awk -i inplace -v OFS=, '{print $0, (FNR==1 ? "#ID" : ARGIND)}' File*.csv
I have a csv file and I am trying to print rows using awk if a certail field ends with a specific string. So for example, I have the below CSV file:
col1,col2,col3
1,abcd,.abcd_efg
2,efgh,.abcd
3,ijkl,.abcd_mno
4,mnop,.abcd
5,qrst,.abcd_uvw
This is the result I am seeking after:
2,efgh,.abcd
4,mnop,.abcd
But I am getting a different result. This is the awk command I am using:
cat file.csv | awk -F"," '{if ($3 ~ ".abcd" ) print $0}'
and This is the result I am getting:
1,abcd,.abcd_efg
2,efgh,.abcd
3,ijkl,.abcd_mno
4,mnop,.abcd
5,qrst,.abcd_uvw
I event tried the below, but no matched is returned so it didn't work:
cat file.csv | awk -F"," '{if ($3 ~ ".abcd$" ) print $0}'
Any clue what the issue might be? Am I using the wrong expression to get this result?
EDIT: This is another command I tried where I tried Kent's solution, but it didn't work:
cat file.csv | awk -F"," '$3 ~ "[.]abcd"'
First of all the cat in cat file|awk ... is useless, just awk ... file
Your input text has no single comma, how come you set FS=","?
If you want to do exact String compare, use $3 == "whatever" instead of $3 ~ /regex/
So your codes could be changed into:
awk '$3 == ".abcd"' file
If you really love regex, and want to do it in regex match way:
awk '$3 ~ "[.]abcd$"' file
or
awk '$3 ~ /^[.]abcd$/' file
depends on what you required.
You may modify your awk command as followed,
$ cat file.csv | awk '$3 ~ /\.abcd$/ {print $0}'
2 efgh .abcd
4 mnop .abcd
Brief explanation,
$3 ~ /.abcd$/: if $3 matches the regex .abcd$, print $0
According to your modified question, you may change the awk command to:
cat file.csv | awk -F, '$3 ~ /\.abcd$/ {print $0}'
I want to compare second column of 1st file with 1st column of 2nd file, if match found display all fields from 1st file and all fields from 2nd file.
file1:
"971525408953","a8:5b:78:5a:dd:dc","TRUE"
"971558216784","ec:1f:72:24:7b:30","TRUE"
"971506509910","e8:50:8b:d8:f3:b5","TRUE"
"971509525934","c8:14:79:b4:bc:da","FALSE"
"971506904830","58:48:22:83:87:7f","TRUE"
file2:
"fc:e9:98:1e:a2:a2",2016-03-07 23:39:29,"TRUE"
"c8:14:79:b4:bc:da",2016-03-08 04:26:06,"TRUE"
"78:a3:e4:87:df:19",2015-12-30 01:22:42,"TRUE"
"18:f6:43:b1:82:47",2016-03-08 08:38:41,"TRUE"
"58:48:22:83:87:7f",2015-12-22 01:22:42,"TRUE"
output expected:
"c8:14:79:b4:bc:da",2016-03-08 04:26:06,"TRUE","971509525934","c8:14:79:b4:bc:da","FALSE"
"58:48:22:83:87:7f",2015-12-2201:22:42,"TRUE","971506904830","58:48:22:83:87:7f","TRUE"
But if i run following command i get this output without n[$2] and n[$3]
awk -F"," 'NR==FNR { n[$2] = $1; next } ($1 in n) {print $1,$2,$3,n[$1],n[$2],n[$3] }' file1 file2
"c8:14:79:b4:bc:da",2016-03-0804:26:06,"TRUE","971509525934",, "58:48:22:83:87:7f",2015-12-22 01:22:42,"TRUE","971506904830",,
Can any one help me on this?
awk -F"," -v OFS="," 'NR==FNR { n[$2] = $1$2$3; next } ($1 in n) {print $1,$2,$3, n[$1] }' file1 file2
output:
"c8:14:79:b4:bc:da",2016-03-08 04:26:06,"TRUE","971509525934""c8:14:79:b4:bc:da""TRUE"
"58:48:22:83:87:7f",2015-12-22 01:22:42,"TRUE","971506904830""58:48:22:83:87:7f""TRUE"
Ok I have a csv file I need to split based on a column value which is fine, but I cannot get the headers to print in each file.
Currently I use:
awk "FS =\",\" {output=$3\".csv\"; print $0 > output}" test.csv
Which splits the files file based on column 3, but I don't know how to add the header to each file.
I've searched high & low but can't find a solution that will work in a one liner...
UPDATE
OK to date we have a working one liner:
awk -F, "NR==1{hdr=$0;next}!($3 in files){files[$3]=1;print hdr>$3\".csv\"}{print>$3\".csv\"}" test.csv
Or in test.awk:
BEGIN{FS=","} NR==1 {hdr=$0;next}!($3 in files) {files[$3]=1;print hdr>$3".csv"}{print>$3".csv"}
Command to run used:
awk -f test.awk test.csv
I really appreciate the help here, I've been trying for hours and have a few things left to work out.
1) Blank line inserted after header
2) Sort the data on specified fields
Further down the line I want to additionally do a row count & cut a reference number from another file is this possible with AWK or am I using the wrong tool for the job?
Thanks again.
UPDATED#2
Blank line after header line
UPDATED
Try this:
On Unix/cygwin (I tested on cygwin):
awk -F, 'NR==1{hdr=$0;next}!($3 in files){files[$3]=1;print hdr"\n">$3".csv"}{print>$3".csv"}' test.csv
Or adding Kent's ideas:
awk -F, 'NR==1{hdr=$0;next}{out=$3".csv"}!($3 in files){files[$3];print hdr"\n">out}{print>out}' test.csv
On windows cmd (not tested):
awk -F, "NR==1{hdr=$0;next}!($3 in files){files[$3]=1;print hdr\"\n\">$3\".csv\"}{print>$3\".csv\"}" test.csv
This stores the header line in test.csv to hdr. For the next lines it checks if the file name value is already exists. If not then stores its name in the files hash and prints the header line. And anyway it prints the whole line to the file.
Example file:
$ cat test.csv
A,B,C,D
1,2,a,3
4,5,b,4
Output
$ cat a.csv
A,B,C,D
1,2,a,3
$ cat b.csv
A,B,C,D
4,5,b,4
ADDED
If You would like to put the awk script into a file You could try (I cannot test is, sorry).
test.awk
BEGIN{FS=","}
NR==1 {hdr=$0;next}
!($3 in files) {files[$3]=1;print hdr"\n">$3".csv"}
{print>"$3.csv"}
Then You may call it as
awk -f test.awk test.csv
awk -F, 'NR==1{h=$0;next}{out=$3".csv";
if!(out in a)print h> out; print $0 > out;a[out]}' test.csv
Try something like this:
awk -F, '
BEGIN {
getline header
}
{
out=$3".csv"
if (!($3 in seen)) {
print header > out
}
print $0 > out
seen[$3]
}' test.csv
Windows version: (Not tested)
awk " FS =\",\"
BEGIN {
getline header
}
{
out=$3\".csv\"
if (!($3 in seen)) {
print header > out
}
print $0 > out
seen[$3]
}" test.csv
awk '{ output=$3".csv"; if( !($0 in a)) print "header" > output; a[$0]
print > output}' FS=, test.csv