Questions tagged [shell-script]
Questions about shell scripts, executable files that are interpreted by a shell (bash, zsh, etc.). Check scripts with https://shellcheck.net before posting.
16,646 questions
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Creating in Linux files in GB or MB range by various size by read a file
In Linux with Bash, there is the File numbers_in_one_line.
In this file there is only one line with several numbers, all separated by spaces.
These numbers are the value in bytes for creating files ...
- 531
0
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1
answer
33
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Counting unique IP addresses per hour in existing log files
I am trying to determine the number of unique web visitors to my website each hour. The log files (access*.log) contain many lines looking similar to this.
192.168.211.85 - - [29/Sep/2024:10:17:02 -...
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1
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Why does cd '' succeed in bash?
Maybe I'm missing it, but I don't find it documented that cd '' should succeed. Since there is no directory with the name '', it seems obvious that it should fail. For example,
mydir=
cd -- "$...
- 1,069
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How should one choose whether to utilise ~ or $HOME? [duplicate]
Context
When utilising the IEEE Standard 1003.1-2017 Shell Command Language, I frequently want to reference the value which $HOME contains.
However, two methods of dynamically acquiring the path are ...
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1
answer
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bash -n is a not documented in manpages or info documents [closed]
Even though bash -n is a valid and widely used option, some manpages don't clearly document it in the bash options section, even though it is implemented. It's also not in the GNU Bash Reference ...
- 1,166
0
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1
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83
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How to create splittet random files and join them with dmsetup
In Linux in Bash, there is a script, a part of the script is this
while true ; do
echo
awk -v x=$(<"$TEMPDIR"size_container_in_byte) -v n=$(<"$TEMPDIR"parts) 'BEGIN{...
- 531
0
votes
1
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103
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How to compare output of a program with a reference value in a shell script?
I have my own implementation of a Redis server which I'd like to test through a shell script.
The general idea is to feed it with some commands through nc, and since nc prints the output of my program ...
- 111
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2
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97
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How to redirect output from a program that waits for input
Following this post I created my own version of the script, with the difference that user and password are forwarded from the environment variables:
#!/bin/zsh
pamtester login $user authenticate <&...
- 101
0
votes
2
answers
87
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how do i use pv in a script that has a seq for loop
I have a script that has a for loop in it that runs a specific amount of times, and I was wondering if it is possible to implement the pv command in my script to add a progress bar.
Here is my code:
...
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1
answer
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How do you know if a package would be upgraded or downgraded by apt?
If you are about to run command
sudo apt-get install --allow-downgrades <pkg>/<target-release>
how do you know if the package would be downgraded or upgraded before running the command? I ...
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2
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How can I pick random items from a list, but some more often than others, in a Bash config file? [closed]
In Linux, using Bash, I have two scripts:
script.sh is the main script, and
script_config.sh is the configuration for script.sh.
In script.sh, I do source script_config.sh to load all the config ...
- 531
0
votes
2
answers
85
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List and count ciphers used by cryptsetup in /dev/mapper devices
In my Linux Computer there are many files called file1, file2, file3 ... in /dev/mapper/.
Now I want to have an overview from the files what cipher is used how often.
I tried this
for i in /dev/...
- 531
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2
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How to analyse a number of different datasets with a script and save the output for each dataset in a different new directory?
I am interested in analysing 50 different datasets with a script and saving the output of each of the 50 analyses in 50 different corresponding directories. To avoid doing this manually, how could ...
0
votes
2
answers
79
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How to "catch" the output of a command? [duplicate]
I'm struggling with the vocabulary here, so I'll ask this way:
On an embedded system (Raspberry Pi) I use, there is a command invoked as follows:
$ pin-control poll 25
This command "polls"...
- 3,727
5
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1
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My bash script keeps telling me my directory doesn't exist even though it does [duplicate]
I have a script and when I run it, it returns
Directory not found: ~/Pictures/Wallpaper
The script is as follows:
#!/bin/bash
# Check if the wallpaper directory exists
if [ ! -d "$WALLPAPER_DIR&...
