Programming :: Bash There Will Be Empty Lines At The End Of The File?
Mar 26, 2011
Using awk I pull the first field of a random line from my datafile.myvar1=`awk -F" " 'NR=='$randline' {printf "%s", $1}' myfileThis works fine. The problem is there will be empty lines at the end of the file. Rather than using awkto filter out blank lines I would like to figure this out first.So I test $myvar1 for a blank string after setting $randline to one that I know is blank:test -z "$myvar1" && echo "true" || echo "false"But, this returns "false"? So the string is not zero length. Why? It's a tab-separated file. Is awk storing the tab with the $1 field or something.This is where I get headache. I try to echo my variable to see what it looks like.
echo "$myvar1"
outputs: nothing
echo "My variable is [$myvar1]"
outputs: [y variable is [
Why is the closing bracket at the beginning? What character could be stored in $myvar1 that would do such a thing and how did it get there?
For example, I have a text file with data which lists numerical values from two separate individuals
Code: Person A 100 200 300 400 500 600 700 800 900 1000 1100 1200
Person B 1200 1100 1000 900 800 700 600 500 400 300 200 100
How would I go about reading the values for each Person, then being able to perform mathematical equations for each Person (finding the sum for example)?
I have a file witch I need to list 10 line by 10 lines with something like press enter to go on in between. Well, the problem is that i have absolutely no idea on how to implement this.
I would like to know how I can get the ouput from the following dmidecode command in example 1 to look like example 2 without having to grep -v all the unwanted lines.Is there a way in awk or sed?Example 1
Code: Processor Information Socket Designation: Socket 1 CPU 1
I'm trying to search through some pdf files and I'm doing so by converting them to text files using pdftotext which is fine but I'm trying to get the number of occurrences in a paragraph of different words and it's adding a new line character at what it thinks is the right hand margin. I'm trying to remove all these singe new line characters but keep the doubles and I can't seem to work it out. i.e.
This is some text that has been broken. Another paragraph. becomes This is some text that has been broken. Another paragraph
So I need to write a bash script that can read lines and column 3 from a file. It needs to start on line 16 and read every 20th line starting from there. But the value that it reads needs to be checked, should it be too great I need it to shut the program down.I'm pretty new to bash, but my ultimate goal is being able to safely run a program on a GPU for an extended period of time with out worrying about it overheating. I have a command that outputs information from the GPU every second, and I can save this to a file. So all I really need is something to read and check that file, I played around a bit with the awk command and can't get it to work within my for loop with dynamic variable.
I would like to parse an input file in which there are two columns per each row. We want to see how many lines are duplicated where we define duplicate to be having the same second field and different first field. For instance if the input file looks like the following:
I want to remove duplicate or multiple similar lines from multiple files. I.e. if I have four files file1.txt file2.txt file3.txt and file4.txt and would like to find and remove similar lines from all these files keeping only one line from these similar lines. I only that uniq can be used to remove similar lines from a sorted file.
Here the description of the issue I am having.I am writing a bash test script which reads lines from a file, builds ISO messages, sends them to a server, reads the response with response code and reports the result of the test to a file or on the screen.The message that I need to send is 94 characters long.Here's the portion of a code that I initially wrote:
#~ Open socket. exec 3<>/dev/tcp/172.26.0.25/9991 #~ Send msg.
I am using embedded Linux. File open is successful. The file has all the permissions. It is present in current directory too. The size is about 27KB. But s.st_size says it is zero.
i have two files with thousands of line, I am trying to combine these two files but i want to insert each line of one file to the another file after certain lines. I am using awk with the following command but it does not work.cat file1 | awk ' { print $0; if (NR%3004==0) {print "file2"}}' > outputfile
I am a final year student doign Computer systems engineering and just been introduced to linux. While still strugling to catch up with the commands, I am now given an assignment under shell scripting.I seriously am strugling to understand this question, can you please assist me.Here follows the assignment:
Operating Systems III Some tips e.g. (test if a file is empty, if it is then display "file is empty" otherwise display
For example, I have a file called "file" like this one: type=strongsubj len=1 word=absolve pos=verb stemmed=y priorpolarity=positive type=strongsubj len=1 word=unique pos=adj stemmed=n priorpolarity=neutral type=strongsubj len=1 word=absolutely pos=adj stemmed=n priorpolarity=neutral type=weaksubj len=1 word=taking pos=verb stemmed=y priorpolarity=positive type=weaksubj len=1 word=friend pos=noun stemmed=n priorpolarity=positive type=weaksubj len=1 word=usually pos=adverb stemmed=n priorpolarity=positive type=strongsubj len=1 word=purecolor pos=anypos stemmed=n priorpolarity=negative type=strongsubj len=1 word=accusingly pos=anypos stemmed=n priorpolarity=negative
I want to add the plural for the noun, for example if find this line: type=weaksubj len=1 word=friend pos=noun stemmed=n priorpolarity=positive will add one more line : type=weaksubj len=1 word=friends pos=noun stemmed=n priorpolarity=positive where we add "s" for the word friend I did try to do like that: <code> cat file | while read LINE ; do
set -- ${line} if [[ "${4#pos1=}" == "noun" ]];then #I tried this line but it doesn't work properly: v3==$(echo $line |sed 's/$3/$s') #I want to find the third word "word=friend" in that line and add "s" after that word # I don't know what command to add this new line "$v3" to the file ??? done </code>
Every now and then I have to indent the lines in my script to 4 space characters. I generally do it line by line. Is there an automated command in vi using which I can indent some set of lines to desired number of space characters in one go.
i am on processing text tasks And i found that if you assign a text to a variable is chomp'ed automatically the newline
Code:
variable=$(cat file.txt)
The problem is i can only access the items/lines using:
Code:
for line in $variable do echo $line # Other commands done
how do i convert this to an indexed array. More importantly, how do i get access to individual $line[0], ..., $line[n] Another thing, if the file.txt, has lines with spaces it is a mess using the for...in..., but echoing prints line by line...o_0
I have a plain text file with 360 lines of varying length text. How do I add a comma or other symbol to the end of each line so that I can convert the file to csv format that I can open in a spreadsheet (45 rows, 8 columns). That means each 8 lines of text forms 8 columns, with 45 rows.
I am trying to read certain lines within a file and give the output of the certain lines that dont equal my value, I think showing you would be easier. There is multiples of these inside one file...
Code:
LV Name /dev/vg00/lvol1 LV Status available/syncd LV Size (Mbytes) 300lable/syncd
[code]....
I want to read everything in the file, if the status is not available then it should display the name (directly above status). If they are all availbale then do nothing. I think I know how to do it which includes putting the info in string form and placing in hash but it is proving to be out of my skill range.
To save on the writing of WAY to many files with very little in them, I want to put it all in one file and read a specific few lines. There will be six variables to be read at a time. Format is as such:
//Set 1 string name 5 12
[code]....
From name to 5th number is a set. The name will be of different lengths for each set. This will be a big file of probably 40+ sets. My problem lies in reading one and only one set be it set 5 or set 34. It needs to be done in C++.
I'm trying to come up with ideas for a simple way to strip a specific "entry" from a text file.I know tools like sed and perl can remove specific lines from a file but I haven't been able to come up with an elegant way to do my group of lines.In my file, the first "Location" line and the "SVNPath" line should be unique every time... but are they enough to strip out the whole set of the group plus the trailing one line of white space separating each group? Add to this, my file will grow as new entries are added (always appended to the end) but new entries will have the same formatting.
I'm trying to extract specific lines from a flat file. I need lines that fall within a range of coordinates. The -F can be either ! or = If the line is in this set range I need all of the data on that line. ranges lat 36 to 39 and longitude -74 to -84
I've been trying to sort this out for several hours and I?m totally lost? I?ve been searching around, but haven?t found the solution to my problem. I have a directory with 100 files. I need to copy 10 lines of each files (let?s say from line 45 to 55) into one unique file. So I guess I could use sed ?w, but I didn?t manage to write the right script. I also tried using a loop to create 100 different files, each one with the 10 lines) to concatenate them later on. But I only got 1 file, not 100.
I have a very, very large log file (360MB) that I'm trying to thin out. As it turns out the majority of this file has entries that aren't necessary so I'm attempting to build a command that will strip these out. The following command works to display only the data that I do not want:
This displays exactly the data I want to delete from the file by displaying the expression and six lines above it and five lines below it. However I'm at a loss as to how to remove this data from the output and display everything else. I looked into the -v option with grep redirecting the output to a new file:
However it doesn't work, the new file is the same size as the old one. What am I doing wrong? Is there a better method of doing this? I'm a bit out of my element since the method I'd normally use can't handle files of this size.
