I am pretty new to Bash and scripting in general and could use some help. Each word in the first file is separated by \n while the second file could contain anything. If the string in the first file is not found in the second file, I want to output it. Pretty much "check if these words are in these words and tell me the ones that are not"
File1.txt contains something like:
dog
cat
fish
rat
file2.txt contains something like:
dog
bear
catfish
magic ->rat
I know I want to use grep (or do I?) and the command would be (to my best understanding):
$foo.sh file1.txt file2.txt
Now for the script...
I have no idea...
grep -iv $1 $2
Give this a try. This is straight forward and not optimized but it does the trick (I think)
while read line ; do
fgrep -q "$line" file2.txt || echo "$line"
done < file1.txt
There is a funny version below, with 4 parrallel fgrep and the use of an additional result.txt file.
> result.txt
nb_parrallel=4
while read line ; do
while [ $(jobs | wc -l) -gt "$nb_parralel" ]; do sleep 1; done
fgrep -q "$line" file2.txt || echo "$line" >> result.txt &
done < file1.txt
wait
cat result.txt
You can increase the value 4, in order to use more parrallel fgrep, depending on the number of cpus and cores and the IOPS available.
With the -f flag you can tell grep to use a file.
grep -vf file2.txt file1.txt
To get a good match on complete lines, use
grep -vFxf file2.txt file1.txt
As #anubhava commented, this will not match substrings. To fix that, we will use the result of grep -Fof file1.txt file2.txt (all the relevant keywords).
Combining these will give
grep -vFxf <(grep -Fof file1.txt file2.txt) file1.txt
Using awk you can do:
awk 'FNR==NR{a[$0]; next} {for (i in a) if (index(i, $0)) next} 1' file2 file1
rat
You can simply do the following:
comm -2 -3 file1.txt file2.txt
and also:
diff -u file1.txt file2.txt
I know you were looking for a script but I don't think there is any reason to do so and if you still want to have a script you can jsut run the commands from a script.
similar awk
$ awk 'NR==FNR{a[$0];next} {for(k in a) if(k~$0) next}1' file2 file1
rat
Related
I'm comparing the results of two files for lines in one that are not in the other using grep -v -f file1.txt file2.txt > result.txt
Let's say my files look like;
file1.txt
alex
peter
zoey
file2.txt
alex
john
peter
zoey
So result.txt should contain john
This is to be run inside a Jenkins job, and jenkins ends up not happy with creating an empty result.txt if there are no differences between the two.
I can't just do a blind diff/no diff output, I specifically need to know which lines differ if there are any.
Is there a neater way to run this command to not create a file if there are no results?
EDIT: Try conditionally running the command with the quiet option -q (which will exit when one match is found and save time). Then once the first match is found (meaning the files are different), you will run the same command and output it to your file.
Try this: (EDIT taken from Charles Duffy's comment)
#!/usr/bin/env bash
if grep -qvf file1.txt file2.txt
then
grep -vf file1.txt file2.txt > output.txt
echo "Differences exist. File output.txt created."
else
echo "No difference between the files detected"
fi
Or with less code and one line:
grep -qvf file1.txt file2.txt && grep -vf file1.txt file2.txt > output.txt
Could you do something as simple as removing the file if it's empty?
Solution #1:
grep -v -f file1.txt file2.txt > result.txt
[[ $? -ne 0 ]] && 'rm' -f result.txt
grep should generate a non-zero return code for an empty output
quote the rm command to ensure not calling any aliases
use the -f to keep silent any messages should the file not exist (shouldn't happen, but doesn't hurt to code for this anyway)
Solution #2:
grep -v -f file1.txt file2.txt > result.txt
[[ ! -s result.txt ]] && 'rm' -f result.txt
-s => file exists and is greater than 0 in size
! -s => file doesn't exist or file exists and is 0 in size
'rm' -f ... same explanation as for solution #1
You can use this awk for conditional differential output file creation:
awk 'NR==FNR{a[$1]; next} !($1 in a){b[$1]} END{
if (length(b) > 0) for (i in b) print i > "result.txt"}' file1.txt file2.txt
Output file result.txt will only be created when there is any output data to be written due to length(b) > 0 check.
This should work for your case
out=$(grep -v -f file1.txt file2.txt); [[ -n "$out" ]] && echo "$out" > results.txt
Using grep && grep. Positive result:
$ grep -q -m 1 -v -f file1 file2 && grep -v -f file1 file2 > out1
$ cat out1
john
and negative:
$ grep -q -m 1 -v -f file1 file1 && grep -v -f file1 file1 > out2
$ cat out2
cat: out2: No such file or directory
It exits the first grep after the first match to quicken its execution but still its execution time at the worst could be twice the runtime of one grep.
Another way, another awk:
$ awk -v outfile=out3 '
NR==FNR {
a[$0]
next
}
($0 in a==0) {
print $0 > outfile # file is only opened when there is a match
}' file1 file2
$ cat out3
john
That awk won't recognize partial matches.
I need some assistance on the below.
File1.txt
aaa:/path/to/aaa:777
bob:/path/to/bbb:700
ccc:/path/to/ccc:600
File2.txt
aaa:/path/to/aaa:700
bbb:/path/to/bbb:700
ccc:/path/to/ccc:644
I should iterate file2.txt and if aaa exists in File1.txt, then i should compare the file permission. If the file permission is same for aaa in both the files then ignore.
If they are different then write them in the output.txt
So in above case
Output.txt
aaa:/path/to/aaa:700
ccc:/path/to/ccc:644
How can i achieve this in unix shell script? Please suggest
I agree with the comment of #Marc that you should try something before asking here.
However, the following answer is difficult to find when you never have seen the constructions, so I give you something to study.
When you want to parse line by line, you can start with
while IFS=: read -r file path mode; do
comparewith=$(grep "^${file}:${path}:" File2.txt | cut -d: -f3)
# compare and output
done < File1.txt
For large files that will become very slow.
You can first filter the lines you want to compare from File2.txt.
You want to grep strings like aaa:/path/to/aaa:, including the last :. With cut -d: -f1-2 you might be fine with your inputfile, but maybe it is better to remove the last three characters:
sed 's/...$//' File1.txt.
You can let grep use the output as a file with expressions using <():
grep -f <(sed 's/...$//' File1.txt) File2.txt
Your example files don't show the situation when both files have identical lines (that you want to skip), you will need another process substitution to get that working:
grep -v -f File1.txt <(grep -f <(sed 's/...$//' File1.txt ) File2.txt )
Another solution, worth trying yourself, is using awk (see What is "NR==FNR" in awk? for accessing 2 files).
comm - compare two sorted files line by line
According to manual, comm -13 <file1> <file2> must print only lines unique to <file2>:
$ ls
File1.txt File2.txt
$ cat File1.txt
aaa:/path/to/aaa:777
bbb:/path/to/bbb:700
ccc:/path/to/ccc:600
$ cat File2.txt
aaa:/path/to/aaa:700
bbb:/path/to/bbb:700
ccc:/path/to/ccc:644
$ comm -13 File1.txt File2.txt
aaa:/path/to/aaa:700
ccc:/path/to/ccc:644
$ # Nice!
But it doesn't check for lines in <file1> that are "similar" to corresponding lines of <file2>. I. e. it won't work as you want if File1.txt has line BOB:/path/to/BOB:700 and File2.txt has BBB:/path/to/BBB:700 since it will print the latter (while you want it not to be printed).
It also won't do what you want if strings bbb:/path/to/bbb:700 and bbb:/another/path/to/bbb:700 are supposed to be "identical".
I have two files, file1.txt and file2.txt. Each has an identical number of lines, but some of the lines in file1.txt are empty. This is easiest to see when the content of the two files is displayed in parallel:
file1.txt file2.txt
cat bear
fish eagle
spider leopard
snail
catfish rainbow trout
snake
koala
rabbit fish
I need to assemble these files together, such that the empty lines in file1.txt are filled with the data found in the lines (of the same line number) from file2.txt. The result in file3.txt would look like this:
cat
fish
spider
snail
catfish
snake
koala
rabbit
The best I can do so far, is create a while read -r line loop, create a counter that counts how many times the while loop has looped, then use an if-conditional to check if $line is empty, then use cut to obtain the line number from file2.txt according to the number on the counter. This method seems really inefficient.
Sometimes file2.txt might contain some empty lines. If file1.txt has an empty line and file2.txt also has an empty line in the same place, the result is an empty line in file3.txt.
How can I fill the empty lines in one file with corresponding lines from another file?
paste file1.txt file2.txt | awk -F '\t' '$1 { print $1 ; next } { print $2 }'
Here is the way to handle these files with awk:
awk 'FNR==NR {a[NR]=$0;next} {print (NF?$0:a[FNR])}' file2 file1
cat
fish
spider
snail
catfish
snake
koala
rabbit
First it store every data of the file2 in array a using record number as index
Then it prints file1, bit it thest if file1 contains data for each record
If there is data for this record, then use it, if not get one from file2
One with getline (harmless in this case) :
awk '{getline p<f; print NF?$0:p; p=x}' f=file2 file1
Just for fun:
paste file1.txt file2.txt | sed -E 's/^ //g' | cut -f1
This deletes tabs that are at the beginning of a line (those missing from file1) and then takes the first column.
(For OSX, \t doesn't work in sed, so to get the TAB character, you type ctrl-V then Tab)
a solution without awk :
paste -d"#" file1 file2 | sed 's/^#\(.*\)/\1/' | cut -d"#" -f1
Here is a Bash only solution.
for i in 1 2; do
while read line; do
if [ $i -eq 1 ]; then
arr1+=("$line")
else
arr2+=("$line")
fi
done < file${i}.txt
done
for r in ${!arr1[#]}; do
if [[ -n ${arr1[$r]} ]]; then
echo ${arr1[$r]}
else
echo ${arr2[$r]}
fi
done > file3.txt
I have one file with the date like below,let say file name is file1.txt:
2013-12-29,1
Here I have to increment the number by 1, so it should be 1+1=2 like..
2013-12-29,2
I tried to use 'sed' to replace and must be with variables only.
oldnum=`cut -d ',' -f2 file1.txt`
newnum=`expr $oldnum + 1`
sed -i 's\$oldnum\$newnum\g' file1.txt
But I get an error from sed syntax, is there any way for this. Thanks in advance.
Sed needs forward slashes, not back slashes. There are multiple interesting issues with your use of '\'s actually, but the quick fix should be (use double quotes too, as you see below):
oldnum=`cut -d ',' -f2 file1.txt`
newnum=`expr $oldnum + 1`
sed -i "s/$oldnum\$/$newnum/g" file1.txt
However, I question whether sed is really the right tool for the job in this case. A more complete single tool ranging from awk to perl to python might work better in the long run.
Note that I used a $ end-of-line match to ensure you didn't replace 2012 with 2022, which I don't think you wanted.
usually I would like to use awk to do jobs like this
following is the code might work
awk -F',' '{printf("%s\t%d\n",$1,$2+1)}' file1.txt
Here is how to do it with awk
awk -F, '{$2=$2+1}1' OFS=, file1.txt
2013-12-29,2
or more simply (this will file if value is -1)
awk -F, '$2=$2+1' OFS=, file1.txt
To make a change to the change to the file, save it somewhere else (tmp in the example below) and then move it back to the original name:
awk -F, '{$2=$2+1}1' OFS=, file1.txt >tmp && mv tmp file1.txt
Or using GNU awk, you can do this to skip temp file:
awk -i include -F, '{$2=$2+1}1' OFS=, file1.txt
Another, single line, way would be
expr cat /tmp/file 2>/dev/null + 1 >/tmp/file
this works if the file doesn't exist or if the file doesnt contain a valid number - in both cases the file is (re)created with a value of 1
awk is the best for your problem, but you can also do the calculation in shell
In case you have more than one rows, I am using loop here
#!/bin/bash
IFS=,
while read DATE NUM
do
echo $DATE,$((NUM+1))
done < file1.txt
Bash one liner option with BC. Sample:
$ echo 3 > test
$ echo 1 + $(<test) | bc > test
$ cat test
4
Also works:
bc <<< "1 + $(<test)" > test
I have two files.
file1.txt:
Afghans
Africans
Alaskans
...
where file2.txt contains the output from a wget on a webpage, so it's a big sloppy mess, but does contain many of the words from the first list.
Bashscript:
cat file1.txt | while read LINE; do grep $LINE file2.txt; done
This did not work as expected. I wondered why, so I echoed out the $LINE variable inside the loop and added a sleep 1, so i could see what was happening:
cat file1.txt | while read LINE; do echo $LINE; sleep 1; grep $LINE file2.txt; done
The output looks in terminal looks something like this:
Afghans
Africans
Alaskans
Albanians
Americans
grep: Chinese: No such file or directory
: No such file or directory
Arabians
Arabs
Arabs/East Indians
: No such file or directory
Argentinans
Armenians
Asian
Asian Indians
: No such file or directory
file2.txt: Asian Naruto
...
So you can see it did finally find the word "Asian". But why does it say:
No such file or directory
?
Is there something weird going on or am I missing something here?
What about
grep -f file1.txt file2.txt
#OP, First, use dos2unix as advised. Then use awk
awk 'FNR==NR{a[$1];next}{ for(i=1;i<=NF;i++){ if($i in a) {print $i} } } ' file1 file2_wget
Note: using while loop and grep inside the loop is not efficient, since for every iteration, you need to invoke grep on the file2.
#OP, crude explanation:
For meaning of FNR and NR, please refer to gawk manual. FNR==NR{a[1];next} means getting the contents of file1 into array a. when FNR is not equal to NR (which means reading the 2nd file now), it will check if each word in the file is in array a. If it is, print out. (the for loop is used to iterate each word)
Use more quotes and use less cat
while IFS= read -r LINE; do
grep "$LINE" file2.txt
done < file1.txt
As well as the quoting issue, the file you've downloaded contains CRLF line endings which are throwing read off. Use dos2unix to convert file1.txt before iterating over it.
Although usng awk is faster, grep produces a lot more details with less effort. So, after issuing dos2unix use:
grep -F -i -n -f <file_containing_pattern> <file_containing_data_blob>
You will have all the matches + line numbers (case insensitive)
At minimum this will suffice to find all the words from file_containing_pattern:
grep -F -f <file_containing_pattern> <file_containing_data_blob>