5
votes
2answers
268 views

How is the inplace modification of a file being done?

What does the "inplace" modification of a file e.g. via sed -i or perl -i mean? My question is about how this inplace modification is done. Is the file copied the modification is done in the copy and ...
2
votes
5answers
508 views

How to use the sed command to only show the first column and last column in a text file

I need some help to figure out how to use the sed command to only show the first column and last column in a text file. Here is what I have so far for column 1: cat logfile | sed 's/\|/ /'|awk ...
4
votes
7answers
520 views

How to split a filename list in 5GB sets?

I have a pretty big list of files which I like to group in smaller list of 5GB each for further processing. The file list is in the following form: "size" (from du) "tab" "absolute path", like this ...
6
votes
1answer
845 views

How can I replace a string in a file(s)?

Replacing strings in files based on certain search criteria is a very common task. How can I replace string foo with bar in all files in the current directory? do the same recursively for sub ...
1
vote
2answers
294 views

Printing and deleting the first line of a file using `sed`

I can print the first line of a file using sed -n 1p file.txt I can delete the first line of a file using sed -i 1d file.txt Is there a way to print-and-delete in sed? Kind of like a FIFO pop() ...
3
votes
2answers
172 views

Join: Two files - but only append last two columns

Given the files: 1.txt 1, abc, 123, 456, 789 2, lmn, 123, 456, 789 3, pqr, 123, 456, 789 2.txt 1, abc, 123, 000, 000 3, lmn, 123, 000, 000 9, opq, 123, 000, 000 OUTPUT.txt ID, NAME, X, ...
1
vote
2answers
366 views

reading from a file and changing its pattern into an array?

I have a CSV file containging entries like this : ipaddress,VLAN,VLANid 10.192.168.1,vlan-xyz,3 10.192.168.1,vlan-abc,8 10.192.168.1,vlan-mnp,11 10.192.163.24,vlan-llz,3 10.192.163.24,vlan-bbz,5 ...
1
vote
4answers
81 views

How to find what device a file is on (and use that in a script)?

I want to find out what device my file is on so that I can use it in a script. I can get this far: $ df . Filesystem 512-blocks Used Available Capacity Mounted on /dev/disk0s2 498438976 ...
3
votes
5answers
384 views

Print non-existent files from a pipe input

I have a directory of lots of .PDF and .JPG files. There should be a .JPG file for each .PDF with the same name. I'm trying to use a command to find .PDF files that doesn't have a .JPG file. My ...
2
votes
5answers
432 views

Replacing lines in files with file contents

I have several files which contain some PHP includes and I want to substitute them with the file contents. The file looks like foo <?php include("file1.php"); ?> bar baz <?php ...
9
votes
3answers
5k views

Delete the first n bytes of files

I've got an extreme problem, and all of the solutions I can imagine are complicated. According to my UNIX/Linux experience there must be an easy way. I want to delete the first 31 bytes of each file ...
2
votes
3answers
945 views

Delete files if contents do not match pattern

There are hundreds of .html files in a directory. I need to delete files that don't contain word bluecar in their contents. I thought sed with rm would do that, but I don't know how to combine them.
8
votes
6answers
232 views

Grab certain contents of a file

So I know tools exist for this problem because I've heard about them, but I don't know what they are. I want to do something like filter out all data but the usernames in /etc/passwd. For example, I ...