There are some data files being imported with header names on the first row and others dont have headers. The ones that are with headers are having always "company" as first field on the first row. For loading them into DB I need to get rid of the first row. So I need to write .sh scrict that deletes first row only of those files that have first column first row="company". I guess I need to combine awk with if statement but I dont know exactly how.
if head -n 1 input.csv | cut -f 1 -d ',' | grep company
then tail -n +2 input.csv > output.csv
else
cp input.csv output.csv
fi
If you're sure the string "company" appears only as 1st field on headers, you can go this way
sed -e /^company,/d oldfile > newfile
supposing the separator is a comma.
Another solution :
if [ head -1 oldfile | grep -q "^company,"] ; then
sed -e 1d oldfile > newfile
else
cp oldfile newfile
fi
No if needed. Just do it straight forward as you stated your requirements:
Print the first line unless it starts with company:
strip_header_if_present() {
IFS='' read -r first_line
echo "$first_line" | grep -v ^company,
Now print the remaining lines:
cat
}
To use this shell function:
strip_header_if_present < input.csv > output.csv
Related
I try to retrieve a line from a file without using a loop.
myFile.txt
val1;a;b;c
val2;b;d;e
val3;c;r;f
I would like to get the line where the second column is b.
If I do grep "b" myFile.txt then both first and second line will be outputed.
If I do cat myFile.txt | cut -d ';' -f2 | grep "b" then the output will just be b whereas I'd like to get the full line val2;b;d;e.
Is there a way of reaching the desired results without using a loop as below ? My file being huge it wouldn't be nice looping through it again and again.
while read line; do
if [ `echo $line | cut -d ';' -f2` = "b" ]; then
echo $line
fi
done < myFile.txt
Given your input file, The below one-liner should work:
awk -F";" '$2 == "b" {print}' myFile.txt
Explanation:
awk -F";" ##Field Separator as ";"
'$2 == "b" ##Searches for "b" in the second column($2)
{print}' ##prints the searched line
Using:
grep:
grep '^[^;]*;b;' myFile.txt
sed:
sed '/^[^;]*;b;/!d' myFile.txt
Output is the same for both:
val2;b;d;e
I have file.txt exemplary here:
This line contains ABC
This line contains DEF
This line contains GHI
and here the following list.txt:
contains ABC<TAB>ABC
contains DEF<TAB>DEF
Now I am writing a script that executes the following commands for each line of this external file list.txt:
take the string from column 1 of list.txt and search in a third file file.txt
if the first command is positive, return the string from column 2 of list.txt
So my output.txt is:
ABC
DEF
This is my code for grep/echo with putting the query/return strings manually:
if grep -i -q 'contains abc' file.txt
then
echo ABC >output.txt
else
echo -n
fi
if grep -i -q 'contains def' file.txt
then
echo DEF >>output.txt
else
echo -n
fi
I have about 100 search terms, which makes the task laborious if done manually. So how do I include while read line; do [commands]; done<list.txt together with the commands about column1 and column2 inside that script?
I would like to use simple grep/echo/awkcommands if possible.
Something like this?
$ awk -F'\t' 'FNR==NR { a[$1] = $2; next } {for (x in a) if (index($0, x)) {print a[x]}} ' list.txt file.txt
ABC
DEF
For the lines of the first file (FNR==NR), read the key-value pairs to array a. Then for the lines of the second line, loop through the array, check if the key is found on the line, and if so, print the stored value. index($0, x) tries to find the contents of x from (the current line) $0. $0 ~ x would instead take x as a regex to match with.
If you want to do it in the shell, starting a separate grep for each and every line of list.txt, something like this:
while IFS=$'\t' read k v ; do
grep -qFe "$k" file.txt && echo "$v"
done < list.txt
read k v reads a line of input and splits it (based on IFS) into k and v.
grep -F takes the pattern as a fixed string, not a regex, and -q prevents it from outputting the matching line. grep returns true if any matching lines are found, so $v is printed if $k is found in file.txt.
Using awk and grep:
for text in `awk '{print $4}' file.txt `
do
grep "contains $text" list.txt |awk -F $'\t' '{print $2}'
done
The problem is the following I have a file that each line has this form:
id|lastName|firstName|gender|birthday|joinDate|IP|browser
i want to sort alphabetically all the firstnames in that file and print them one on each line but each name only once
i have created the following program but for some reason it creates an infinite loop:
array1=()
while read LINE
do
if [ ${LINE:0:1} != '#' ]
then
IFS="|"
array=($LINE)
if [[ "${array1[#]}" != "${array[2]}" ]]
then
array1+=("${array[2]}")
fi
fi
done < $3
echo ${array1[#]} | awk 'BEGIN{RS=" ";} {print $1}' | sort
NOTES
if [ ${LINE:0:1} != '#' ] : this command is used because there are comments in the file that i dont want to print
$3 : filename
array1 : is used for all the seperate names
Wow, there's a MUCH simpler and cleaner way to achieve this, without having to mess with the IFS variable or using arrays. You can use "for" to do this:
First I created a file with the same structure as yours:
$ cat file
id|lastName|Douglas|gender|birthday|joinDate|IP|browser
id|lastName|Tim|gender|birthday|joinDate|IP|browser
id|lastName|Andrew|gender|birthday|joinDate|IP|browser
id|lastName|Sasha|gender|birthday|joinDate|IP|browser
#id|lastName|Carly|gender|birthday|joinDate|IP|browser
id|lastName|Madson|gender|birthday|joinDate|IP|browser
Here's the script I wrote using "for":
#!/bin/bash
for LINE in `cat file | grep -v "^#" | awk -F'|' '{print$3}' | sort -u`
do
echo $LINE
done
And here's the output of this script:
$ ./script.sh
Andrew
Douglas
Madson
Sasha
Tim
Explanation:
for LINE in `cat file`
Creates a loop that reads each line of "file". The commands between ` are run by linux, for example, if you wanted to store the date inside of a variable you could use "VARDATE=`date`".
grep -v "^#"
The option -v is used to exclude results matching the pattern, in this case the pattern is "^#". The "^" character means "line begins with". So grep -v "^#" means "exclude lines beginning with #".
awk -F'|' '{print$3}'
The -F option switches the column delimiter from the default (the default is a space) to whatever you put between ' after it, in this case the "|" character.
The '{print$3}' prints the 3rd column.
sort -u
And the "sort -u" command to sort the names alphabetically.
I have a bunch of files in the following format.
A.txt:
some text1
more text2
XXX
more text
....
XXX
.
.
XXX
still more text
text again
Each file has at least 3 lines that start with XXX. Now, for each file A.txt I want to write all the lines till the 3rd occurrence of XXX (in the above example it is till the line before still more text) to file A_modified.txt.
I want to do this in bash and came up with grep -n -m 3 -w "^XXX$" * | cut -d: -f2 to get the corresponding line number in each file.
Is is possible to use head along with these line numbers to generate the required output?
PS: I know a simple python script would do the job but I am trying to do in this bash for no specific reason.
A simpler method would be to use awk. Assuming there's nothing but files of interest in your present working directory, try:
for i in *; do awk '/^XXX$/ { c++ } c<=3' "$i" > "$i.modified"; done
Or if your files are very big:
for i in *; do awk '/^XXX$/ { c++ } c>=3 { exit }1' "$i" > "$i.modified"; done
head -n will print out the first 'n' lines of the file
#!/bin/sh
for f in `ls *.txt`; do
echo "searching $f"
line_number=`grep -n -m 3 -w "^XXX$" $f | cut -d: -f1 | tail -1`
# line_number now stores the line of the 3rd XXX
# now dump out the first 'line_number' of lines from this file
head -n $line_number $f
done
I have number of files which have similar names like
DWH_Export_AUSTA_20120701_20120731_v1_1.csv.397.dat.2012-10-02 04-01-46.out
DWH_Export_AUSTA_20120701_20120731_v1_2.csv.397.dat.2012-10-02 04-03-12.out
DWH_Export_AUSTA_20120801_20120831_v1_1.csv.397.dat.2012-10-02 04-04-16.out
etc.
I need to get number before .csv(1 or 2) from the file name and put it into end of every line in file with TAB separator.
I have written this code, it finds number that I need, but i do not know how to put this number into file. There is space in the filename, my script breaks because of it.
Also I am not sure, how to send to script list of files. Now I am working only with one file.
My code:
#!/bin/sh
string="DWH_Export_AUSTA_20120701_20120731_v1_1.csv.397.dat.2012-10-02 04-01-46.out"
out=$(echo $string | awk 'BEGIN {FS="_"};{print substr ($7,0,1)}')
awk ' { print $0"\t$out" } ' $string
for file in *
do
sfx=$(echo "$file" | sed 's/.*_\(.*\).csv.*/\1/')
sed -i "s/$/\t$sfx/" "$file"
done
Using sed:
$ sed 's/.*_\(.*\).csv.*/&\t\1/' file
DWH_Export_AUSTA_20120701_20120731_v1_1.csv.397.dat.2012-10-02 04-01-46.out 1
DWH_Export_AUSTA_20120701_20120731_v1_2.csv.397.dat.2012-10-02 04-03-12.out 2
DWH_Export_AUSTA_20120801_20120831_v1_1.csv.397.dat.2012-10-02 04-04-16.out 1
To make this for many files:
sed 's/.*_\(.*\).csv.*/&\t\1/' file1 file2 file3
OR
sed 's/.*_\(.*\).csv.*/&\t\1/' file*
To make this changed get saved in the same file(If you have GNU sed):
sed -i 's/.*\(.\).csv.*/&\t\1/' file
Untested, but this should do what you want (extract the number before .csv and append that number to the end of every line in the .out file)
awk 'FNR==1 { split(FILENAME, field, /[_.]/) }
{ print $0"\t"field[7] > FILENAME"_aaaa" }' *.out
for file in *_aaaa; do mv "$file" "${file/_aaaa}"; done
If I understood correctly, you want to append the number from the filename to every line in that file - this should do it:
#!/bin/bash
while [[ 0 < $# ]]; do
num=$(echo "$1" | sed -r 's/.*_([0-9]+).csv.*/\t\1/' )
#awk -e "{ print \$0\"\t${num}\"; }" < "$1" > "$1.new"
#sed -r "s/$/\t$num/" < "$1" > "$1.mew"
#sed -ri "s/$/\t$num/" "$1"
shift
done
Run the script and give it names of the files you want to process. $# is the number of command line arguments for the script which is decremented at the end of the loop by shift, which drops the first argument, and shifts the other ones. Extract the number from the filename and pick one of the three commented lines to do the appending: awk gives you more flexibility, first sed creates new files, second sed processes them in-place (in case you are running GNU sed, that is).
Instead of awk, you may want to go with sed or coreutils.
Grab number from filename, with grep for variety:
num=$(<<<filename grep -Eo '[^_]+\.csv' | cut -d. -f1)
<<<filename is equivalent to echo filename.
With sed
Append num to each line with GNU sed:
sed "s/\$/\t$num" filename
Use the -i switch to modify filename in-place.
With paste
You also need to know the length of the file for this method:
len=$(<filename wc -l)
Combine filename and num with paste:
paste filename <(seq $len | while read; do echo $num; done)
Complete example
for filename in DWH_Export*; do
num=$(echo $filename | grep -Eo '[^_]+\.csv' | cut -d. -f1)
sed -i "s/\$/\t$num" $filename
done