Tagged Questions
4
votes
6answers
92 views
Getting two fields from same line together
I've got a situation where I've got several lines, and I need two different fields out of each of them. To be specific, I have a list of references in a bibliography and I want to get the last name ...
1
vote
2answers
93 views
How to record every transaction using Bash
I have a file with debit credit and withdrawal transactions. I need a bash script that records the balance after every transaction. So file is like this:
D:11/02/12:1000.50
C:11/03/12:300
...
1
vote
4answers
183 views
print last field from line + alternative for awk
Due to technical reason on my Solaris machine, I can't use awk in order to print the last field in line.
What are the other alternatives to awk that print the last field from line (using cut or tr ...
11
votes
4answers
272 views
How to do a continous 'wc -l' with gnu texttools?
I know of course that
cat logfile.txt | wc -l
120
will tell me the number of lines in a file.
Whereas
tail -f logfile.txt
will show me the new lines that another program writes to logfile.txt.
...
4
votes
2answers
145 views
Why doesn't this xargs command work?
I wanted to delete all .sh extensions so did this:
ls *.sh | xargs -I {} mv {} `basename {} .sh`
However it doesn't work, it behaves like basename returns unchanged file name.
Why is it behaving ...
3
votes
3answers
46 views
How to separate numerical values from identifiers
I'm currently writing a shell script that seperate values from their identifiers (retrieved from grep).
For example, if I grep a certain file I will retrieve the following information:
value1 = 1
...
5
votes
1answer
84 views
array[@] output all messed up?
I've got this code:
Unix+=("Stock List")
while read line; do
result=$(wget -O - -o /dev/null "http://finance.yahoo.com/d/quotes.csv?s=$line&f=sl1&e=.csv" | tr ',' ' ' | tr '"' ' ')
...
3
votes
1answer
103 views
Printing the line after or before a regular expression match in Bash
Given a string like the following:
BASH - Mplayer Playlist Shuffle
http://www.youtube.com/watch?v=IB7SCPtbJM8
metalx1000
BASH - Playing Music
http://www.youtube.com/watch?v=S_-EGoLYCXY
metalx1000
...
2
votes
2answers
159 views
How to read by multiple lines instead of line-by-line
I see that in my code I can modify a line if the entire code is based on that line. Example: <p class="example">this is an example Happy Holidays</p>. However if the </p> tag is ...
3
votes
2answers
264 views
How to delete commands in history matching a given string?
I need to delete all commands in my history matching a string. I've tried:
$ history | grep searchstring | cut -d" " -f2 | history -d
-bash: history: -d: option requires an argument
$ history | grep ...
2
votes
3answers
252 views
Substitute placeholders in template
Say I have a shell configuration file config like this:
HOST=localhost
PORT=8080
Now I have a template template like this:
The host is <%= @HOST %>
The port is <%= @PORT %>
How do I ...
3
votes
2answers
156 views
Limit stdout from a continuously running process
I haven't had much luck finding an answer to my problem, but maybe I'm not asking for it correctly.
I have a process I startup like the following:
nohup ping 127.0.0.1 > log.txt >2>&1 &
...
0
votes
2answers
159 views
Easiest way to find/replace in a file using a list?
I have a file, foo.txt, and a regexp I want to find in that file. Each time I find the regexp, I want to take a line from another file, bar.txt, and substitute it in for the regexp match I found in ...
0
votes
1answer
259 views
Remove a block of lines between two patterns [duplicate]
Possible Duplicate:
Show only text between 2 matching pattern
In a bash script using sed how can I remove a block of lines beginning with -pattern a- and ending with -pattern b- where the ...
2
votes
4answers
193 views
How to do an IF statement from the result of a executed command
I am trying to do an IF statement from the output of an executed commmand. Here is how I am trying to do it, but it doesn't work. Does anyone know the right way to do this?
if [ "`netstat -lnp | ...
6
votes
6answers
829 views
Text processing - join lines with commas
I have more than 1000 lines in a file. The file starts as follows (line numbers added):
1. Station Name
2. Station Code
3. A N DEV NAGAR
4. ACND
5. ABHAIPUR
6. AHA
7. ABOHAR
8. ABS
9. ABU ROAD
10. ...
2
votes
5answers
2k views
Bash iterate over a list of strings
I have this bash script:
for opt in string1 string2 string3 ... string99
do somestuff
It works, but I would like to replace the explicit listing of my strings with a file which actually contains ...
9
votes
5answers
228 views
How to count rows ordered by the first field in bash
Here is a snippet from the INPUT:
...
####################
Bala Bela;XXXXXX12345;XXXXXX12345678;A
SERVER345Z3.DOMAIN.com0
SERVER346Z3.DOMAIN.com0
SERVER347Z3.DOMAIN.com0
SERVER348Z3.DOMAIN.com0
...
4
votes
6answers
249 views
What is the easiest way to check if column A and B values goes both ways with AWK? [closed]
What is the easiest way to check if column A and B values goes both ways?
Output to check:
Mike John
John Mike
Pamela Barbara
Barbara Pamela
Mike Paul
Roger Paul
Desired output
Mike <-> ...
4
votes
2answers
605 views
delete first line of file only if blank using sed
I have a solution for this in awk:
awk '{if (NR==1 && NF==0) next};1' somefile
but was unable to find one that worked in sed. E.g.,
sed -i.bak '/^$/{1,1d;}' somefile
ended up deleting ...
3
votes
4answers
468 views
Strip spaces after single capital letters with sed
I am writing a bash script to automatically generate some other files, and I have to format some strings a certain way. Specifically, the last problem I'm having is formatting a string that has ...
4
votes
1answer
234 views
inexact text search
Is there any utility like grep or even uniq but for inexact search or I should write it myself?
I mean it will look at 90% (number may vary) matching, or smth like that.
For example I have file with ...
3
votes
2answers
4k views
How do I delete the first n lines of an ascii file using shell commands?
I have multiple files that contain ascii text information in the first 5-10 lines, followed by well-tabulated matrix information. In a shell script, I want to remove these first few lines of text so ...
0
votes
3answers
786 views
Count number of lines in files then compare which has more (BASH)
I need to count the number of lines in x files and compare which has more.
The one I've done only takes two files and compares them. Any idea how to make it x amount of files?
echo Enter the ...
3
votes
3answers
178 views
How to perform an action only on the first line?
sed 's/.\(.*\)/\1/' myfile
Say myfile contains:
abc
def
ghi
I want to remove the first character only from the first line but the above removes it from all the line.
16
votes
4answers
15k views
How to add a newline to the end of a file?
Using version control systems I get annoyed at the noise when the diff says No newline at end of file.
So I was wondering: How to add a newline at the end of a file to get rid off those messages?
3
votes
5answers
180 views
evaluate multiple patterns from program output and write into pattern specific files
I have a script outputting some value/numbers and I want to split those into two files. I am looking at something like:
./runme.sh | grep 'ook' >> ook.out | grep 'eek' >> eek.out
Where ...
2
votes
4answers
777 views
Trouble getting awk output in for loop
I'm trying to create a script that will check a website for a word. I have a few to check so I'm trying to input them via another file.
The file is called "testurls". In the file I list the keyword ...
5
votes
2answers
2k views
How to insert a new line after every second line?
sed/bash/wharever :D
INPUT:
sadf
asdf
yxcv
cxv
eqrt
asdf
OUTPUT:
sadf
asdf
yxcv
cxv
eqrt
asdf
2
votes
1answer
439 views
How to read a hexdump byte by byte in bash or awk?
This is the hexadecimal output of an IPv6 TCP packet captured with tcpdump:
6000 0000 0018 0620 0000 0000
0000 0000 0000 0000 0000 0001 0000 0000
0000 0000 0000 0000 0000 0002 *0026 0026
0000 ...
2
votes
2answers
349 views
Script to prepend the files path to a file recursively
I work as a grader and files submitted to me end up in a folder named with the student's name which is itself inside a specific folder on my linux share.
Currently I go through each source file and ...
2
votes
2answers
497 views
Why does a bash here-string add a trailing newline char?
The following examples show that a newline is added to a here-string.
Why is this done?
xxd -p <<<'a'
# output: 610a
xxd -p <<<'a
'
# output: 610a0a
4
votes
4answers
533 views
How can I remove a specific string from a file only if there are other lines in the file?
How can I remove a specific string from a file ONLY if there are other lines in the file?
For example, don't touch this file:
cat file.txt
ASDF
but remove "ASDF" from this file:
cat file.txt
ASDF
...
2
votes
2answers
432 views
How to temporarily disable the Escape key in a Terminal?
I am parsing keyboard input via read -n 1 and I haven't found a way to distinguish between an actual key-press of the Escape key and the first Escape character (byte) of a control sequence generated ...
4
votes
3answers
742 views
Read and process a string, char by char, yet allow user to simple line edit the input
I want to incrementally read a line of input from the terminal,
and allow the user some basic line editing functionality; INS, DEL, RIGHT, LEFT HOME, END, BACKSPACE
Each time the string is ...
7
votes
4answers
625 views
How do I find the overlap of two strings in bash?
I have two strings. For the sake of the example they are set like this:
string1="test toast"
string2="test test"
What I want is to find the overlap starting at the beginning of the strings. With ...
2
votes
1answer
1k views
Why is 'while.. read.. <<EOL' performing variable expansion, yet <file and | don't?
Aside from the variable expansion mentioned in the question's heading, I also experience another alarming issue when reading inline data to <<EOL... When the data contains a backtick `, it ...
6
votes
3answers
8k views
How to use bash script to read binary file content?
I want to read a character and then a fixed length of string (the string is not null terminated in the file, and its length is given by the preceding character).
How can I do this in a bash script? ...
1
vote
1answer
456 views
Keep newlines in output of cut
Let's imagine we have a file:
foo bar
foo1 bar1
I want to cut every second word in every line, so I want file to look like this:
foo
foo1
I am trying to use cut -d ' ' -f -1 but what I get is:
...
16
votes
7answers
21k views
Looping through files with spaces in the names?
I wrote the following script to diff the outputs of two directores with all the same files in them as such:
#!/bin/bash
for file in `find . -name "*.csv"`
do
echo "file = $file";
diff ...
4
votes
1answer
500 views
Is there a search utility which can binary split search a large sorted (sequential) text file?
Yes, I know it sounds odd. Sequential and Binary-splits don't mix.. That is unless the sequence is the byte offset within the file itself...
I've scrambled together a binary split search in bash ...
3
votes
3answers
2k views
Is it possible in bash, to start reading a file from an arbitary byte count offset?
I want to locate a date which is somewhere in an 8 GB log (text).
Can I somewhat bypass a full sequential read, and first do binary splits of the file (size), or somehow navigating the filesystem ...
7
votes
2answers
404 views
What governs the limits of shell brace expansion?
In this example I refer to the expansion of a sequence of integers, but perhaps(?) the limits would be relevant to all aspects of brace expansion.. This more general view is also of interest to me.
...
3
votes
3answers
840 views
Fast way to build a test file with every second listed in YYYY-mm-dd HH:MM:SS format
I want to create a large test file with lines containg dates listed by the second, but my method is taking inordinately long... (or at least, that's how it feels :) ... 43 minutes to create only ...
2
votes
3answers
2k views
Extracting tokens from a line of text
Using bash scripting and grep/awk/sed, how can I split a line matching a known pattern with a single character delimiter into an array, e.g. convert token1;token2;token3;token4 into a[0] = token1 … ...
