All Questions
2,867 questions
0
votes
1
answer
72
views
How exactly are results being passed among processes via the pipes?
So Unix follows a uniform approach to I/O that allows programs to connect via pipes. I also know that to do that it uses file descriptors. But I heard someone saying that pipes allow attaching the ...
- 121
0
votes
2
answers
103
views
How to sum all disk size in Linux?
We have some Linux servers with several disks.
[root@xxxxx~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 ...
- 459
6
votes
1
answer
719
views
bash pipe loses data when command crashed
Consider this simple program (abort.py) that writes some text to stdout and stderr and then crashed (abort()).
import os
import sys
print("end stdout")
print("end stderr", file=...
- 171
4
votes
1
answer
533
views
How can I use a terminal emulator as an efficient application launcher?
The Problem
I've used various application launchers like rofi, albert, wofi, dmenu, and others throughout my Linux years. While they have their pros and cons, one thing has always bothered me: they're ...
- 61
2
votes
1
answer
163
views
select in a script
In Linux in Bash in a Script i use this:
#!/bin/bash
while true; do
while true; do
read -r -p 'enter number [4-999]: ' num
if [[ $num =~ ^([4-9]|[1-9][0-9]{1,2})$ ]]; then
...
- 539
0
votes
0
answers
32
views
Why does `if [ -d $EMPTY_VAR ]` return true? [duplicate]
I have written a Bash script which doesn't behave quite as I expected.
It contains the following lines of code.
TARGET_FOLDER=$1
echo "TARGET_FOLDER: $TARGET_FOLDER"
if [ ! -d $TARGET_FOLDER ...
- 937
-4
votes
2
answers
108
views
How to write in Linux in Bash in shellscript a part that can do something like this
How to write in Linux in Bash in shellscript a part that can do something like this
enter a number
must be in a range from 4-999
if not, ask again to enter
enterednumber * 5 * randomnumber [1-9] (...
- 539
0
votes
0
answers
34
views
How to only suppress warning outputs from cryptsetup?
In Linux in Bash i run a script with some cryptsetup calls like
--luks2-metadata-size=16k --luks2-keyslots-size=256k .... luksFormat ....
that brings Warning outputs.
I know and understand, but i ...
- 539
1
vote
1
answer
30
views
How to see the content of an appointment in a queue of commands of AT command
I know i can see the schedule with atq, but this brings me only the timedate of the execution and not wich command wil be executed.
[root@myserver ~]# atq
1Thu Oct 31 04:45:00 2024 a root
Using at -...
- 11
2
votes
1
answer
27
views
subset my .fam file using a .txt file of names
I have a .fam file in plink format, looks like this
1 I001.HO 0 0 1 1
2 I002.HO 0 0 1 1
3 IREJ-T006.HO 0 0 1 1
4 IREJ-T009.HO 0 0 1 1
5 IREJ-T022.HO 0 0 1 1
6 IREJ-T023.HO ...
- 23
0
votes
1
answer
46
views
Open 2 mate-terminal instances and run commands
I am trying to set up a script that runs 2 mate-terminal instances, each with a different command.
The script is set up as a cronjob.
The problem is, while the script works fine when executed manually,...
- 131
0
votes
0
answers
27
views
how to change error (std-err) color [duplicate]
Because standard error is a separate device in UNIX-like environments, and programs or shell scripts can redirect their errors to it, it would be logical to configure terminals (any displayer) to ...
- 1
4
votes
2
answers
280
views
How to find and list all symlinks in a short form?
I have a large set of directories and files, along with many symlinks that typically point to a directory called "shared" or to a directory or a file underneath the "shared" ...
- 804
1
vote
2
answers
57
views
How to loop over a list of extensions to check that files of each type exist?
I have the following directory structure:
main_dir/
│ ├── randstr1.randstr2.tar.gz
│ ├── randstr3.randstr4.tar.gz
│ ├── randstr5.randstr6.tar.gz
│ ├── randstr7.ext2
│ └── randstr8.ext3
...
- 229
1
vote
1
answer
97
views
add a randomize option in a bash script
in a bash script i do run this:
seq 1 $(<howmany.txt) | xargs -I% -n1 -P$(<parallel.txt) mycommand --infile file% --option A --outfile file%.new
it works.
the values in howmany.txt and parallel....
- 539
1
vote
1
answer
78
views
Why does tar command create this directory structure when extracting a tar file?
I have created this simple directory structure:
$ tree testdir/
testdir/
├── subdir1
│ ├── file1.txt
│ └── file2.txt
├── subdir2
│ ├── file3.txt
│ └── file4.txt
and would like to archive the ...
- 229
0
votes
3
answers
95
views
how to process a sequence of items in groups of N at a time
Sequentially one after another:
for i in $(ls -1) ; do command $i ; done
All at one time:
for i in $(ls -1); do \
( \
command $i ; done ; \
) & \
done; wait
How to say only for example 4 or ...
- 539
0
votes
2
answers
41
views
Capture and print on the exact match from a file
I am trying to use grep to match only a specific part of a row in a file.
The file is a huge csv file with some columns containing json with commas so it is hard to figure out which column what I am ...
- 121
4
votes
2
answers
282
views
Invalid date when setting one computer's clock from another
I have the following code in a Bash script, which takes the current date/time and sets it via SSH on a target computer:
ssh <user>@<target> "date --set '$(date)'"
This was ...
0
votes
1
answer
88
views
How to add some random data at certain places in a file
With my Computer, it runs a Linux kernel and bash, i will make a technical-experiment.
I have a file, file.dat, size = 1.048.576 byte.
I will add at certain places in file.dat some irregular (1...8 ...
- 539
0
votes
2
answers
62
views
How to append multiple wildcard outputs into separate lines using echo?
very very new to Linux as a whole and doing some relatively simple exercises in bash. I cannot for the life of me figure out how to take multiple outputs from the wildcard character (*) and copy them ...
0
votes
1
answer
70
views
How to prevent a Linux shell from intercepting escape sequence so it can be sent over serial TTY
I am working on an embedded system that is connected over USB serial TTY (i.e. /dev/ttyUSB0), which needs to interpret arrow keys sent via a virtual terminal such as screen. The problem is, the shell (...
- 1
1
vote
0
answers
36
views
Going to the direcory of a file as fast as posible [duplicate]
Is there a way to get to the path of a file as fast as possible and in the least amount of keystrokes.
Context:
Type cd and then paste the path of a file and then have to go back and hit backspace ...
- 11
0
votes
2
answers
107
views
How to copy the value from one "column" to another in Bash?
I have a file with lines:
username="user1" email="[email protected]"
I need to take the username from the email address and replace the username value with it,
so the end result ...
-2
votes
2
answers
49
views
Remove last 9 character in alternate lines of file in unix
I need to remove last 9 character from a file starting from Line number 4 and remove only on alternate lines 6,8.. like that to last Line of file
- 1
0
votes
1
answer
123
views
Strange bash errors for root console
Frequently, when switching my user by root with su -, I get strange bash error messages in the rxvt console, or even in a TTY. They happen even after a complety system upgrade from scratch, so it is ...
- 489
1
vote
2
answers
59
views
How to modify this git alias so it can be run without the need to put multiword commands in quotation?
I have this alias:
git config --global alias.all '!f() { ls -R -d */.git | xargs -I{} bash -c "echo {} && git -C {}/../ $1"; }; f'
It currently works fine when I run it like :
git ...
- 133
-3
votes
1
answer
76
views
How to convert multiple columns to rows in shell (unpivoting)
I have a tab separated table with hundreds of columns and rows, like that:
OTUId AC0184 AC0250 AC0257 AC0258 AC0262 AC0263 AC0289 AC0293
OTU549024624 51659 0 0 0 0 0 0 0
OTU565712448 108 0 0 0 0 0 0 0 ...
1
vote
2
answers
68
views
Use sed to insert a character in an xml file
I have an xml file with content following this format:
<type:color>000000</type:color>
<type:color>FFFFFF</type:color>
The information within the tags are hex colors (many ...
- 33
-2
votes
2
answers
255
views
runuser: execute commands without use of quotation marks?
Overview
I'm attempting to execute commands as a different user without using quotation marks as well as making sure the executed command isn't inheriting environment from the parent shell.
runuser ...
- 150
0
votes
2
answers
117
views
How can I properly harden my system against some basic exploits like modifications of .bashrc?
I recently read a section on bashrc in the ubuntuusers wiki, in which a possible attack vector for privilege escalation is pointed out. Attackers, or malicious programs, could modify the bashrc or ...
- 193
-4
votes
3
answers
125
views
show which of a list of filenames do not exist in a given list of directories
I have a long list of filenames like 20231121_150111.jpg... in a text file (one filename per line).
And another list of directories. Those directories contain files.
How can I check and show which ...
- 539
16
votes
5
answers
1k
views
How can UserA programmatically replace a text string within a file they own that's located in /etc?
A non-root linux user owns a text file that's located in /etc, where the non-root linux user does not have permission to create files. The non-root linux user can edit the file manually via vi without ...
- 163
-3
votes
1
answer
246
views
Find files in a directory modified in the last 24 hours without using the "find" command [closed]
Is there a way to find the files modified in a specific directory in the last 24 hours without using the find command, using only the ls command?
0
votes
1
answer
73
views
Running command 'cat /proc/<pid>/stat | cut -d" " -f29' to get stack pointer , is always showing stack pointer as zero
Iam trying to get the stack pointer of some thread using the /proc//stat, whenever i run the command,cat /proc/<pid>/stat | cut -d" " -f29 i end up getting zero, but when i run sudo ...
12
votes
2
answers
5k
views
Check if current user can run sudo without requiring a password
I want to check if the current user running a BASH shell script has access to passwordless sudo or not. If they don't, I'd rather have the script exit rather than prompting them for a password.
- 305
1
vote
0
answers
217
views
Bash terminal lagging one input behind
After a recent update, I've noticed that working on any terminal for more than a few minutes causes a delay between inputting a keypress and seeing it reflected on the screen.
Specifically, if I were ...
- 173
0
votes
1
answer
68
views
Bash script to find certain files and add their names to another file
When I find a file whose size is 12kb I want to copy the file name to new file input.xml
#!/bin/bash
if [ $(find /root -type f -size +12k) ]
then
grep -r -i -s "the name of file to find it&...
- 11
0
votes
0
answers
74
views
keep sudo effective without password after update sudo package itself
I want to write an automation script in Bash that requires frequent use of the sudo command. To avoid entering my password repeatedly after the sudo timeout, I've tried the following:
#!/bin/bash
sudo ...
- 187
0
votes
1
answer
41
views
Looking for assistance in expect
I have a bash script that has expect to login to a remote host and run list of commands. It works as expected. It has a flaw, if the user enters the wrong password, the expect script keeps trying the ...
- 1
-2
votes
3
answers
196
views
Bash script: echo output of variable and write to file
I am trying to write a script which will check to see if the contents of a file match a certain value and if so, overwrite it with contents of another file.
Example:
file1 =
A, B, C, D
1, 2, 3, 4
...
0
votes
0
answers
42
views
Command 'cdh' not found appearing at the top of CL when opened
I am new to Ubuntu, and I am using the latest version. Initially, I wanted to create an alias, using:
alias cdh='cd /home/[My name]/'
This was done since I wanted to download video files to a ...
1
vote
1
answer
32
views
Diagnose bash autocomplete issues
I have one binary on my system, fio installed via package manager which doesn't autocomplete files with tab once you've typed fio . I guess this means something must over overridding the autocomplete ...
- 559
4
votes
1
answer
387
views
pipe to a different file descriptor
Following up on Using while loop to ssh to multiple servers, i.e., for
while IFS= read -r -u9 HOST ; do ssh "$HOST" "uname -a" ; done 9< servers.txt
which reads from a ...
- 1,736
0
votes
0
answers
44
views
Using comma separated list to ssh [duplicate]
Following on https://unix.stackexchange.com/a/511859/374303,
whose answer is:
while IFS=, read -r IP ID NAME; do
echo "ssh $IP myprogram $ID $NAME"
done < testfile.txt
However, my ...
- 1,736
0
votes
2
answers
76
views
extract a column from the command output even if it blank bash
I am trying to extract 2nd column from a command output
For example:
$ sudo /usr/sbin/pvs
PV VG Fmt Attr PSize PFree
/dev/sdc1 vgswap lvm2 a-- 16.00g 0
/dev/sdc2 ...
- 1
2
votes
3
answers
110
views
can nohup and disown both still let program run after exiting the shell
I'm discovering the difference between nohup and disown in Ubuntu's bash.
I have while.py.
import time
while True:
print(1)
time.sleep(1)
First, I used ssh to connect to my ubuntu server and ...
- 51
1
vote
1
answer
80
views
How to Set Up Individual Bash History Files for Each Container Alongside a Unified History File?
In my current setup, all of my bash histories are stored in a single file, which is pointed to HISTFILE.
This history includes a history of the host system and all containers.
Along with this history, ...
- 11
4
votes
1
answer
181
views
Will writing to /dev/pts allow me to source ~/.bashrc?
I have several terminal windows already open; I just made a change to ~/.bashrc, and I'd like to run source ~/.bashrc in each of the open terminals.
It seems to me that if I just
source ~/.bashrc | ...
2
votes
1
answer
154
views
How to run python script on login
I am attempting to load a python script that launches a Firefox Geckodriver under Selenium whenever a specific kiosk user logs in to the GUI.
I've tried launching this via .profile, however ...
- 31