Problem
You have defined a variable in a bash script (ie MY_FOLDER) but you also want to dynamically get the parent folder (ie MY_FOLDER can have multiple values).
Solution
Use the dirname as in the following
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MY_FOLDER=/home/user/first_folder/second_folder MY_PARENT_FOLDER=$(dirname $MY_FOLDER) echo $MY_FOLDER echo $MY_PARENT_FOLDER ....... /home/user/first_folder/second_folder /home/user/first_folder |
Problem
You would like to remove some lines from the bash history (ie using cut and paste with wrong values).
Solution
You can use the following, taken from the answer here
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for i in {1..no_of_lines}; do history -d start_line; done |
where start_line is the start of the lines you want to remove and no_of_lines is the number of lines you want to be removed.
Problem
You would like to find the files that contain some specific text, and would like to do it recursively (ie in a project folder), using something simpler than the find command.
Solution
You can use the following in your current top folder to search recursively, case-independent and by displaying the file number that the searched text appears, with the following:
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grep -rin "TextToBeSearched" . |
Problem
You are trying to install/remove a package but you always get an error message about linux message as above:
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Errors were encountered while processing: linux-image-3.13.0-128-generic |
Solution
Try the following:
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rm -rf /var/lib/dpkg/info/linux-image-3.13.0-128-generic.* apt-get purge linux-image-3.13.0-128-generic |
Problem
You have a bash script that accepts parameter(s) but you want to give a default value for a missing parameter.
Solution
For example you have a script that accepts a parameter with the year and month (ie 201703), but you want to give it a default of two months ago if the parameter is missing.
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#!/bin/bash LM=$(date -d '2 month ago' +%Y%m) YEARMONTH=${1:-${LM}} echo $YEARMONTH |
Problem
You would like to find out the serial number of your Lenovo laptop, but without switching it off and taking the battery off.
Solution
You can run the following to get your laptop’s details including the serial number:
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sudo dmidecode -t system |
Taken from the post here
