grep from two variables - bash

I am trying to eliminate the duplicate lines of a list like this.
LINES='opa
opa
eita
eita
argh'
DUPLICATE='opa
eita'
The output I am looking for is argh.
Till now, this is what I tried:
echo -e "$DUPLICATE" | grep --invert-match -Ff- <(echo -e "$LINES")
And:
grep --invert-match -Ff- <(echo -e "$DUPLICATE") <(echo -e "$LINES")
But unsuccessfuly.
I know that I can achieve this if I put the content of $LINES into a file:
echo -e "$DUPLICATE" | grep --invert-match -Ff- FILE
But I'd like to know if this is possible only with variables.

Passing a dash as the file name to -f means "read from stdin". Get rid of it so the file name given to -f is the process substitution.
There's no need for echo -e, and -v is shorter and more common than --invert-match.
echo "$LINES" | grep -vFf <(echo "$DUPLICATE")
Equivalently, using a herestring:
grep -vFf <(echo "$DUPLICATE") <<< "$LINES"

another approach which doesn't require to create a duplicate list separately,
$ awk '{a[$0]++} END{for(k in a) if(a[k]==1) print k}' <<< "$LINES"
count occurrence of each line, print only if it's not duplicated (count==1).

Related

How to remove all symbols after dot [duplicate]

How can I remove all text after a character, in this case a colon (":"), in bash? Can I remove the colon, too? I have no idea how to.
In Bash (and ksh, zsh, dash, etc.), you can use parameter expansion with % which will remove characters from the end of the string or # which will remove characters from the beginning of the string. If you use a single one of those characters, the smallest matching string will be removed. If you double the character, the longest will be removed.
$ a='hello:world'
$ b=${a%:*}
$ echo "$b"
hello
$ a='hello:world:of:tomorrow'
$ echo "${a%:*}"
hello:world:of
$ echo "${a%%:*}"
hello
$ echo "${a#*:}"
world:of:tomorrow
$ echo "${a##*:}"
tomorrow
An example might have been useful, but if I understood you correctly, this would work:
echo "Hello: world" | cut -f1 -d":"
This will convert Hello: world into Hello.
$ echo 'hello:world:again' |sed 's/:.*//'
hello
I know some solutions:
# Our mock data:
A=user:mail:password
With awk and pipe:
$ echo $A | awk -v FS=':' '{print $1}'
user
Via bash variables:
$ echo ${A%%:*}
user
With pipe and sed:
$ echo $A | sed 's#:.*##g'
user
With pipe and grep:
$ echo $A | egrep -o '^[^:]+'
user
With pipe and cut:
$ echo $A | cut -f1 -d\:
user
egrep -o '^[^:]*:'
trim off everything after the last instance of ":"
grep -o '^.*:' fileListingPathsAndFiles.txt
and if you wanted to drop that last ":"
grep -o '^.*:' file.txt | sed 's/:$//'
#kp123: you'd want to replace : with / (where the sed colon should be \/)
Let's say you have a path with a file in this format:
/dirA/dirB/dirC/filename.file
Now you only want the path which includes four "/". Type
$ echo "/dirA/dirB/dirC/filename.file" | cut -f1-4 -d"/"
and your output will be
/dirA/dirB/dirC
The advantage of using cut is that you can also cut out the uppest directory as well as the file (in this example), so if you type
$ echo "/dirA/dirB/dirC/filename.file" | cut -f1-3 -d"/"
your output would be
/dirA/dirB
Though you can do the same from the other side of the string, it would not make that much sense in this case as typing
$ echo "/dirA/dirB/dirC/filename.file" | cut -f2-4 -d"/"
results in
dirA/dirB/dirC
In some other cases the last case might also be helpful. Mind that there is no "/" at the beginning of the last output.

what does grep -v '^#' do

My program looks like this.
ALL=`cat $1 | grep -v '^#' | wc -l`
FINISHED="0"
for i in `cat $1 | grep -v '^#'`; do
echo "PROBE $i"
I will be doing some operation
FINISHED=`echo $FINISHED"+1"|bc`
I will run this script by giving a file name as parameter where a list of probes will be present.
I have 2 questions
What does grep -v '^#' mean. I learnt that '^ is usually used to matching a particular string. But in the file name which I give there is no #. Moreover I am getting the total number of probes for cat $1 | grep -v '^#' | wc -l.
echo $FINISHED"+1"|bc. Here any idea as to why the developer as added |bc?
^ means "start of line"
# is the literal character #
-v means "invert the match" in grep, in other words, return all non matching lines.
Put those together, and your expression is "select all lines that do not begin with #"
| is the pipe character, it takes the output of the command on the left hand side, and uses it as the input of the command on the right hand side. bc is like a command line calculator (to do basic math).
I would use this to exclude comments from the code I'm reading. So all comment lines start with # and I don't want to see them if there are too many of them.
grep -v '^#'
We have different ways for calculation. Pick the one which you like.
a=`echo 1+1 | bc`; echo $a
b=$((1+1)); echo $b
c=`expr 1 + 1`; echo $c
let d=1+1; echo $d

How to compose custom command-line argument from file lines?

I know about the xargs utility, which allows me to convert lines into multiple arguments, like this:
echo -e "a\nb\nc\n" | xargs
Results in:
a b c
But I want to get:
a:b:c
The character : is used for an example. I want to be able to insert any separator between lines to get a single argument. How can I do it?
If you have a file with multiple lines than you want to change to a single argument changing the NEWLINES by a single character, the paste command is what you need:
$ echo -en "a\nb\nc\n" | paste -s -d ":"
a:b:c
Then, your command becomes:
your_command "$(paste -s -d ":" your_file)"
EDIT:
If you want to insert more than a single character as a separator, you could use sed before paste:
your_command "$(sed -e '2,$s/^/<you_separator>/' your_file | paste -s -d "")"
Or use a single more complicated sed:
your_command "$(sed -n -e '1h;2,$H;${x;s/\n/<you_separator>/gp}' your_file)"
The example you gave is not working for me. You would need:
echo -e "a\nb\nc\n" | xargs
to get a b c.
Coming back to your need, you could do this:
echo "a b c" | awk 'OFS=":" {print $1, $2, $3}'
it will change the separator from space to : or whatever you want it to be.
You can also use sed:
echo "a b c" | sed -e 's/ /:/g
that will output a:b:c.
After all these data processing, you can use xargs to perform the command you want to. Just | xargs and do whatever you want.
Hope it helps.
You can join the lines using xargs and then replace the space(' ' ) using sed.
echo -e "a\nb\nc"|xargs| sed -e 's/ /:/g'
will result in
a:b:c
obviously you can use this output as argument for other command using another xargs.
echo -e "a\nb\nc"|xargs| sed -e 's/ /:/g'|xargs

shell script to read contain from file and grep on other file

I am working on shell, I want to write one liner which will read the file contents of file A and execute grep command on file B.
for example, suppose there are two file
dataFile.log which have following value
abc
xyz
... and so on
now read abc and grep on searchFile.log like grep abc searchFile.log
I have shell script for the same but want one liner for it
for i in "cat dataFile.log" do grep $i searchFile.log done;
try this:
grep -f dataFile.log searchFile.log
Note that if you want to grep as fixed string, you need -F, if you want to match the text in dataFile.log as regex, use -E or -P
How about the following: it even ignores blank lines and # comments:
while read FILE; do if [[ "$FILE" != [/a-zA-Z0-9]* ]]; do continue; fi; grep -h pattern "$FILE"; done;
Beware: have not compiled this.
You can use grep -f option:
cat dataFile.log | grep -f searchFile.log
Edit
OK, now I understand the problem. You want to use every line from dataFile.log to grep in searchFile.log. I also see you have value1|value2|..., so instead of grep you need egrep.
Try with this:
for i in `cat dataFile.log`
do
egrep "$i" searchFile.log
done
Edit 2
Following chepner suggestion:
egrep -f dataFile.log searchFile.log

Bash grep variable from multiple variables on a single line

I am using GNU bash, version 4.2.20(1)-release (x86_64-pc-linux-gnu). I have a music file list I dumped into a variable: $pltemp.
Example:
/Music/New/2010s/2011;Ziggy Marley;Reggae In My Head
I wish to grep the 3rd field above, in the Master-Music-List.txt, then continue another grep for the 2nd field. If both matched, print else echo "Not Matched".
So the above will search for the Song Title (Reggae In My Head), then will make sure it has the artist "Shaggy" on the same line, for a success.
So far, success for a non-variable grep;
$ grep -i -w -E 'shaggy.*angel' Master-Music-MM-Playlist.m3u
$ if ! grep Shaggy Master-Music-MM-Playlist.m3u ; then echo "Not Found"; fi
$ grep -i -w Angel Master-Music-MM-Playlist.m3u | grep -i -w shaggy
I'm not sure how to best construct the 'entire' list to process.
I want to do this on a single line.
I used this to dump the list into the variable $pltemp...
Original: \Music\New\2010s\2011\Ziggy Marley - Reggae In My Head.mp3
$ pltemp="$(cat Reggae.m3u | sed -e 's/\(.*\)\\/\1;/' -e 's/\(.*\)\ -\ /\1;/' -e 's/\\/\//g' -e 's/\\/\//g' -e 's/.mp3//')"
If you realy want to "grep this, then grep that", you need something more complex than grep by itself. How about awk?
awk -F';' '$3~/title/ && $2~/artist/ {print;n=1;exit;} END {if(n=0)print "Not matched";}'
If you want to make this search accessible as a script, the same thing simply changes form. For example:
#!/bin/sh
awk -F';' -vartist="$1" -vtitle="$2" '$3~title && $2~artist {print;n=1;exit;} END {if(n=0)print "Not matched";}'
Write this to a file, make it executable, and pipe stuff to it, with the artist substring/regex you're looking for as the first command line option, and the title substring/regex as the second.
On the other hand, what you're looking for might just be a slightly more complex regular expression. Let's wrap it in bash for you:
if ! echo "$pltemp" | egrep '^[^;]+;[^;]*artist[^;]*;.*title'; then
echo "Not matched"
fi
You can compress this to a single line if you like. Or make it a stand-along shell script, or make it a function in your .bashrc file.
awk -F ';' -v title="$title" -v artist="$artist" '$3 ~ title && $2 ~ artist'
Well, none of the above worked, so I came up with this...
for i in *.m3u; do
cat "$i" | sed 's/.*\\//' | while read z; do
grep --color=never -i -w -m 1 "$z" Master-Music-Playlist.m3u \
| echo "#NotFound;"$z" "
done > "$i"-MM-Final.txt;
done
Each line is read (\Music\Lady Gaga - Paparazzi.mp3), the path is stripped, the song is searched in the Master Music List, if not found, it echos "Not Found", saved into a new playlist.
Works {Solved}
Thanks anyway.

Resources