Tagged Questions

3
votes
3answers
497 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 ...
11
votes
6answers
6k 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 ...
3
votes
1answer
278 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 ...
2
votes
5answers
102 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
3answers
672 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
259 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. ...
2
votes
3answers
707 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 … ...
2
votes
4answers
226 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 ...
2
votes
2answers
212 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
164 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