Hello guys I wrote code in linux shell script but the code only read from keyboard i want to change it to read from file for example if i write ./car.sh lamborghini.txt it should give me most expensive model of it.
code is like this:
#!/bin/sh
echo "Choose one of them"
read manu
sort -t';' -nrk3 auto.dat > auto1.dat
grep $manu auto1.dat | head -n1 | cut -d';' -f2
and auto.dat file contains these:
Lamborghini;Aventador;700000
Lamborghini;Urus;200000
Tesla;ModelS;180000
Tesla;ModelX;140000
Ford;Mustang;300000
Ford;Focus;20000
The read command always reads from stdin. You can use redirection < to read the content of a file.
Reading $manu from a file's content
#!/bin/sh
read manu < "$1"
sort -t';' -nrk3 auto.dat | grep "$manu" | head -n1 | cut -d';' -f2
This version of your script expects a file name as a command line parameter. The first line of said file will be stored in $manu. Example:
./car.sh fileWithSelection.txt
The file should contain the text you would have entered in your old script.
Reading $manu from a command line parameter
In my opinion, it would make more sense to interpret the command line parameters directly, instead of using files and passing them to the script.
#!/bin/sh
manu="$1"
sort -t';' -nrk3 auto.dat | grep "$manu" | head -n1 | cut -d';' -f2
Example:
./car.sh "text you would have entered in your old script."
You can try this way but the file Tesla.txt must contain Tesla
#!/bin/sh
read manu < "$1"
awk -F\; -vmod="$manu" '
$1==mod{if($3>a){a=$3;b=$2}}
END{if(b){print "The more expensive "mod" is "b" at "a}}' auto.dat
Related
I'm trying to parse lines from an error log in BASH and then send a certain part out to a BASH variable to be used later in the script and having issues once I try and pass it to a BASH variable.
What the log file looks like:
1446851818|1446851808.1795|12|NONE|DID|8001234
I need the number in the third set (in this case, the number is 12) of the line
Here's an example of the command I'm running:
tail -n5 /var/log/asterisk/queue_log | grep 'CONNECT' | awk -F '[|]' '{print $3}'
The line of code is trying to accomplish this:
Grab the last lines of the log file
Search for a phrase (in this case connect, I'm using the same command to trigger different items)
Separate the number in the third set of the line out so it can be used elsewhere
If I run the above full command, it runs successfully like so:
tail -n5 /var/log/asterisk/queue_log | grep 'CONNECT' | awk -F '[|]' '{print $3}'
12
Now if I try and assign it to a variable in the same line/command, I'm unable to have it echo back the variable.
My command when assigning to a variable looks like:
tail -n5 /var/log/asterisk/queue_log | grep 'CONNECT' | brand=$(awk -F '[|]' '{print $3}')
(It is being run in the same script as the echo command so the variable should be fine, test script looks like:
#!/bin/bash
tail -n5 /var/log/asterisk/queue_log | grep 'CONNECT' | brand=$(awk -F '[|]' '{print $3}')
echo "$brand";
I'm aware this is most likely not the most efficient/eloquent solution to do this, so if there are other ideas/ways to accomplish this I'm open to them as well (my BASH skills are basic but improving)
You need to capture the output of the entire pipeline, not just the final section of it:
brand=$(tail -n5 /var/log/asterisk/queue_log | grep 'CONNECT' | awk -F '|' '{print $3}')
You may also want to consider what will happen if there is more than one line containing CONNECT in the final five lines of the file (or indeed, if there are none). That's going to cause brand to have multiple (or no) values.
If your intent is to get the third field from the latest line in the file containing CONNECT, awk can pretty much handle the entire thing without needing tail or grep:
brand=$(awk -F '|' '/CONNECT/ {latest = $3} END {print latest}')
I need to generate a script from within a script but am having problems because some of the commands going into the new script are being interpreted rather than written to the new file. For example i want to create a file called start.sh in it I want to set a variable to the current IP address:
echo "localip=$(ip addr | grep 'state UP' -A2 | tail -n1 | awk '{print $2}' | cut -f1 -d'/')" > /start.sh
what gets written to the file is:
localip=192.168.1.78
But what i wanted was the following text in the new file:
localip=$(ip addr | grep 'state UP' -A2 | tail -n1 | awk '{print $2}' | cut -f1 -d'/')"
so that the IP is determined when the generated script is run.
What am i doing wrong ?
You're making this unnecessary hard. Use a heredoc with a quoted sigil to pass literal contents through without any kind of expansion:
cat >/start.sh <<'EOF'
localip=$(ip addr | grep 'state UP' -A2 | tail -n1 | awk '{print $2}' | cut -f1 -d'/')
EOF
Using <<'EOF' or <<\EOF, as opposed to just <<EOF, is essential; the latter will perform expansion just as your original code does.
If anything you're writing to start.sh needs to be based on current variables, by the way, be sure to use printf %q to safely escape their contents. For instance, to set your current $1, $2, etc. to be active during start.sh execution:
# open start.sh for output on FD 3
exec 3>/start.sh
# build a shell-escaped version of your argument list
printf -v argv_str '%q ' "$#"
# add to the file we previously opened a command to set the current arguments to that list
printf 'set -- %s\n' "$argv_str" >&3
# pass another variable through safely, just to be sure we demonstrate how:
printf 'foo=%q\n' "$foo" >&3
# ...go ahead and add your other contents...
cat >&3 <<'EOF'
# ...put constant parts of start.sh here, which can use $1, $2, etc.
EOF
# close the file
exec 3>&-
This is far more efficient than using >>/start.sh on every line that needs to append: Using exec 3>file and then >&3 only opens the file once, rather than opening it once per command that generates output.
I am having following syntax for one of my file.Could you please anyone explain me what is this command doing
path = /document/values.txt
where we have different username specified e.g username1 = john,username2=marry
cat ${path} | grep -e username1 | cut -d'=' -f2`
my question here is cat command is reading from the file value of username1 but why why we need to use cut command?
Cat is printing the file. The file has username1=something in one of the lines. The cut command splits this and prints out the second argument.
your command was not written well. the cat is useless.
you can do:
grep -e pattern "$path"|cut ...
you can of course do it with single process with awk if you like. anyway the line in your question smells not good.
awk example:
awk -F'=' '/pattern/{print $2}' inputFile
cut -d'=' -f2`
This cut uses -d'=' that means you use '=' as 'field delimiter' and -f2 will take only de second field.
So in this case you want only the value after the "=" .
for example
echo "filename.pdf" | cut -d'.' -f 1
This way I get the "filename" string.
I'd like to store it in a variable called FILE and then use it like this:
DIR=$PATH/$FILE.txt
So, my script wants to create a file.txt with the same name of the pdf (not a copy of the file, just the name)
This way I tried to assign the result of echo | cut
FILE=
but I get only "path/.txt" so the filename is missing.
FILE=$(echo "filename.pdf" | cut -d'.' -f 1)
So, my script wants to create a file.txt with the same name of the pdf
You can use BASH string manipulation:
s="filename.pdf"
p="${s/%.pdf/.txt}"
echo "$p"
filename.txt
POSIX parameter expansion would read
file=filename.pdf
filename="${file%%.*}" # Two % will remove multiple extensions, if applicable
dir=$path/$filename.txt
I have file.txt with names one per line as shown below:
ABCB8
ABCC12
ABCC3
ABCC4
AHR
ALDH4A1
ALDH5A1
....
I want to grep each of these from an input.txt file.
Manually i do this one at a time as
grep "ABCB8" input.txt > output.txt
Could someone help to automatically grep all the strings in file.txt from input.txt and write it to output.txt.
You can use the -f flag as described in Bash, Linux, Need to remove lines from one file based on matching content from another file
grep -o -f file.txt input.txt > output.txt
Flag
-f FILE, --file=FILE:
Obtain patterns from FILE, one per line. The empty file
contains zero patterns, and therefore matches nothing. (-f is
specified by POSIX.)
-o, --only-matching:
Print only the matched (non-empty) parts of a matching line, with
each such part on a separate output line.
for line in `cat text.txt`; do grep $line input.txt >> output.txt; done
Contents of text.txt:
ABCB8
ABCC12
ABCC3
ABCC4
AHR
ALDH4A1
ALDH5A1
Edit:
A safer solution with while read:
cat text.txt | while read line; do grep "$line" input.txt >> output.txt; done
Edit 2:
Sample text.txt:
ABCB8
ABCB8XY
ABCC12
Sample input.txt:
You were hired to do a job; we expect you to do it.
You were hired because ABCB8 you kick ass;
we expect you to kick ass.
ABCB8XY You were hired because you can commit to a rational deadline and meet it;
ABCC12 we'll expect you to do that too.
You're not someone who needs a middle manager tracking your mouse clicks
If You don't care about the order of lines, the quick workaround would be to pipe the solution through a sort | uniq:
cat text.txt | while read line; do grep "$line" input.txt >> output.txt; done; cat output.txt | sort | uniq > output2.txt
The result is then in output.txt.
Edit 3:
cat text.txt | while read line; do grep "\<${line}\>" input.txt >> output.txt; done
Is that fine?