Tag: bash

Given two directory trees, how can I find out which files differ by content? [closed]

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Bash script to delete all but N files when sorted alphabetically

bash linux ubuntu

It’s hard to explain in the title. I have a bash script that runs daily to backup one folder into a zip file. The zip files are named worldYYYYMMDD.zip with YYYYMMDD being the date of backup. What I want to do is delete all but the 5 most recent backups. Sorting the files alphabetically will list the oldest ones first,

extracting unique values between 2 sets/files

bash command-line linux perl scripting

Working in linux/shell env, how can I accomplish the following: text file 1 contains: text file 2 contains: I need to extract the entries in file 2 which are not in file 1. So ‘6’ and ‘7’ in this example. How do I do this from the command line? many thanks! Answer Explanation of how the code works: If we’re

How can I show the wget progress bar only? [closed]

bash linux sh wget

How do you find the original user through multiple sudo and su commands?

bash linux su sudo unix

When running a script via sudo or su I want to get the original user. This should happen regardless of multiple sudo or su runs inside of each other and specifically sudo su -. Answer Results: Use who am i | awk ‘{print $1}’ OR logname as no other methods are guaranteed. Logged in as self: Normal sudo: sudo su

Generate a value to reflect the average brightness of an image

bash brightness image linux

I need to determine if an image is above a certain brightness. Using a scale of 0 – 255 I want to generate a value within this range to reflect the image brightness. i.e. a white image is 255 and a black image is 0. All this needs to take place via a bash script I am building up at

How can I format my grep output to show line numbers at the end of the line, and also the hit count?

bash grep linux unix

I’m using grep to match string in a file. Here is an example file: grep -i null myfile.txt returns How can I return matched lines together with their line numbers like this: I know -c returns total matched lines, but I don’t how to format it properly to add total null count in front, and I don’t know how to

How to sort files into folders by filetype on bash (with ‘file’ command)?

bash file file-type linux

I have thousands of files without extensions after recovery (mostly pictures). I need to sort them into separate folders by filetype (folders must be created during sort process). I can determine filetype in linux using “file” command. Does somebody have bash script for it? For example: Initial dir contains files: 001, 002, 003, 004. After sorting should be 3 dirs:

Using sed to get an env var from /proc/*/environ weirdness with x00

bash environment-variables linux sed

I’m trying to grovel through some other processes environment to get a specific env var. So I’ve been trying a sed command like: sed -n “s/x00ENV_VAR_NAME=([^x00]*)x00/1/p” /proc/pid/environ But I’m getting as output the full environ file. If I replace the 1 with just a static string, I get that string plus the entire environ file: sed -n “s/x00ENV_VAR_NAME=([^x00]*)x00/BLAHBLAH/p” /proc/pid/environ I

Retrieve plain text script from compiled bash script

bash compilation linux scripting

Some time ago, i wrote some bash scripts for my school. I thought it would be very clever to ‘protect’ them, so i compiled them with shc into a binary file. Some weeks later, i lost the uncompiled scripts and now i have only my binarys left. Is there a way to retrieve the scripts back from the shc generated