Questions tagged [bash]
Questions specific to GNU’s Bourne Again SHell, as opposed to other Bourne/POSIX shells. For questions about Unix shells in general, use the /shell tag instead. For shell scripts with errors/syntax errors, please check them with the shellcheck program (or in the web shellcheck server at https://shellcheck.net) before posting here.
24,262
questions
0
votes
0
answers
7
views
How to use a value from sub shell in parent shell
I'm not used to linux scripting and this is the first time I'm working on it so I'm struggling with the following problem:
Code:
while [ $pct -gt 80 ]; do
flag=1;
ls -tr | while read file; do
...
0
votes
1
answer
14
views
Why are my /usr/local/bin programs being copied to /usr/local/sbin?
I can't seem to reproduce it now, but it seems that some of the programs I add to /usr/local/bin get added to /usr/local/sbin.
I noticed this because I wrote a bash script that seemed to me, for ...
- 1
0
votes
1
answer
24
views
find files that is stored in format yyyy/mm/dd
I have a cron job that runs at 1am and creates an index.html for yesterday and current day in the below yyyy/mm/dd format.
I need to grab day -1 and send to users. How can i achieve this?
-bash-4.2$ ...
- 1
1
vote
4
answers
33
views
Stuck at removing a trailing newline from a string variable
Sometimes simplest things take your time in shell scripting like crazy.
Content='me \n you \n him \n'
echo $Content > Names.txt
When I open the Names.txt it has two empty lines at the end.
I want ...
- 249
1
vote
2
answers
27
views
How can I create a JSON object from an associative array in shell using jo?
I know about How to create JSON from associative array but that's not my problem.
I have this associative array:
declare -A aliases
aliases[Index]=components/Index/Exports
aliases[Shared]=components/...
- 249
0
votes
0
answers
9
views
Turn a script do while to a systemctl service to intercept a tcp connection state
I made a little script that refresh browser, when web-server is down and connection is lost, with an infinite loop do/while true.
I want to turn it in a service for a better and clean solution.
The ...
0
votes
0
answers
22
views
set -o vi in prompt leaves insert mode every time I use arrow keys and has warning bell constantly (bash/ksh)
I might use arrow keys to go back and edit a flag when typing a command in my prompt and doing so constantly kicks me back from insert mode to normal mode. How do I turn this off so it matches the ...
- 67
0
votes
1
answer
26
views
Why is “echo $SHELL” not captured by remote SSH output?
When I capture the output of a remote SSH call using cat, whether in bash or in Python, things work as expected.
E.g, this works just fine:
import subprocess
rc = subprocess.getoutput(“ssh user@host; ...
- 129
0
votes
0
answers
10
views
Subprocess launched inside a chroot created on a codespace with debootstrap fail with /dev/fd/62: No such file or directory
My goal is to standup a chroot with the basic Unix tool-set (bash, cp, touch, cat, etc) and any necessary dependencies need to run apt get inside a codespace. Using debootstrap gets me close. The ...
- 232
1
vote
1
answer
45
views
IP address string manipulation problem
I am trying to build three octets 10.AB.C9 from a 5 digit number: 12ABC
12 = first octet
AB = Second octet
C = Third octet
There are two scenarios with my existing code that can cause an in correct IP ...
- 323
0
votes
1
answer
13
views
Toggle screen resolution with a script, how?
How do I phrase a script that checks screen resolution with xrandr and changes resolution depending on what it is currently? Which is to say, toggles the resolution.
Sample output of xrandr -q
...
- 113
1
vote
1
answer
43
views
Bash output of date in bash script
I wrote this script:
#!/bin/bash
target="1.1.1.1"
while true;
do
ping $target -c 1 -v > /dev/null
if [[ $? -ne 0 ]]; then
echo "$(date +"%d/%m/%y ...
0
votes
2
answers
82
views
Why can't dot files in root directory be moved
There're some files, folders and dot files in a directory like following
|-folder1
|----folder2
|----file.json
|----file2.php
|----.env
|----.dockerfile
|----.someconfig
|----.dockerignore
I run ...
- 1
0
votes
0
answers
13
views
Setting DISPLAY variable on a remote XServer session
I have a CentOS system running an X2go server and I use a client machine to connect to it. I'm trying to do some command-line automation for mouse-clicks using xdotool. The automation is scripted in ...
- 153
0
votes
0
answers
12
views
zsh command expansion applies esacping [duplicate]
I have a string S, for which I want to replace every b character with \\ (two forward slashes).
So this is what I have:
$ S="abc"
$ A=$(echo $S | sed 's/b/\\\\/')
In bash I get the expected ...
1
vote
2
answers
36
views
bash script: copy from a folder to another within a directory and loop the process over multiple directories
I am still a beginner for bash scripting.I am trying to loop copy command to run through multiple directories.
I have set of directories, P1, P2, P3,..P60. Inside each directory there are three ...
- 13
0
votes
3
answers
35
views
Is there an equivalent to /dev/stdout for file descriptors 3-255?
I know that one can often trick command line utilities that expect a file to pipe into stdout out by passing /dev/stdout as the file name.
I'm wondering whether it's possible to make a tool pipe to a ...
- 180
0
votes
0
answers
5
views
How can I reverse backward-search to forwards-search and jump to next item with single type of C-s
I am using solution in unable to forward search Bash history similarly as with CTRL-r.
To search backward in the history for a particular string, type C-r. Typing C-s searches forward through the ...
- 229
0
votes
1
answer
30
views
Pass bash variables to another application
I am trying to read some values from a file, save them in bash variables, and run docker by passing the values as environment variables. The file's structure is as follows:
DB_NAME=db
ROOT_PASS=...
- 1
0
votes
1
answer
23
views
Is it possible to create a ncat loop?
If you had two computers, wanting to control one from another using only ncat, without using telnet, ssh or other networking tools and only two shells, how could i go about that?
I have successfully ...
0
votes
3
answers
36
views
Grep line containing a word OR has length in a specific range?
1598427@931
PDD 220624P00051000 ohlc=0,0,0,0 vol=0 oi=424 nbbo=69@2316/113@532 nbbo2=69@145/113@95
PDD 220617C00051000 ohlc=0,0,0,0 vol=0 oi=434 nbbo=530@1921/710@1496 nbbo2=530@31/710@115
PDD ...
- 103
0
votes
0
answers
18
views
Using install to copy same source file multiple times (with different names) into same destination
I'm trying to use install to write a series of automated steps to setup a subroutine. In one of the sections I need to copy a given file (logback.xml) to a specific location, but I need multiple ...
- 875
0
votes
1
answer
20
views
How to copy a file to a subdirectory path which is the same for multiple directories?
I wrote a git commit hook and tested it out in a repo called myrepo. I would now like to copy it to all the repos I have in my ~/repos folder. To do that I tried:
$ cd ~/repos/myrepo/.git/hooks
$ cp ...
- 1
1
vote
1
answer
44
views
Bash function for 'Deep Replace' in file contents, file name, directory name, allowing for whitespace
On my Ubuntu system, I commonly need to do a 'Deep Replace' in file contents, the file name and directory name. For example when copying source code as a template for another application.
I've put ...
- 121
1
vote
0
answers
14
views
Bash File Completion Creates Python Virtual Environment
Sometimes when I use tab file completion in a bash shell it pauses for one or two seconds before showing tab completion, and creates a Python virtual environment in my current directory.
For example ...
- 11
0
votes
1
answer
28
views
Verifying a hashed salted password that uses yescrypt algorithm
In order to verify a password hash we can use openssl passwd as shown below and explained here
openssl passwd $HASHING-ALGORITHM -salt j9T$F31F/jItUvvjOv6IBFNea/ $CLEAR-TEXT-PASSWORD
However, this ...
- 125
0
votes
0
answers
17
views
Wayland: Execute command in default terminal
In the past, I've been using x-terminal-emulator -e "$COMMAND" to launch commands in a new instance of the default terminal emulator while trying to be as compatible and DE independent as ...
- 168
1
vote
1
answer
50
views
Fuzzy/non-deterministic behaviour for a simple Bash script
[root@localhost ~]# time cpumode
Driver: acpi-cpufreq
Boost: disabled
Governor: ondemand
Average and maximum frequencies now: 2159MHz 2929MHz
Maximum allowed frequency is 3800MHz (out of 4928MHz)...
- 19.5k
2
votes
2
answers
226
views
Using jq in a bash script to get an element with a certain value pattern
I'm calling the homebrew api in a shell script with the goal of getting the App name for the item before trying to install it. Luckily the api provides this in an element called artifacts. Unluckily, ...
- 123
2
votes
1
answer
469
views
ufw "command not found"- but as the root user!
My Debian 11 VPS is running now for about 2 weeks- and today I just wanted to analyse, why my traffic is ~70GiB (counted by bashtop). So somewhere in the net I read about nethogs, that this could help....
- 23
0
votes
3
answers
54
views
Given a weekday name, week of a month, and a year, how to find the date
I can find the last Monday using date -d 'last-monday' +%F but given a weekday name, week of a month, and a year, how to find the date?
e.g. given: Monday, Week 4, June, 2022
output: 2022-06-20
given: ...
- 9
0
votes
0
answers
37
views
AWK command for summary statistics of array with several columns and a grouping variable
I got a data file with time-series data.
Each line of the 5+ GB csv file freqs.csv has the appearance:
start_freq stop_freq measurement1 measurement2 ... measurementk
Frequencies are represented on ...
0
votes
1
answer
54
views
create first come first serve with bash script [closed]
#/bin/bash
sort(){
for ((i = 0; i<$n; i++))
do
for((j = 0; j<`expr $n - $i - 1`; j++))
do
if [ ${arrival_time[j]} -gt ${arrival_time[$((j+...
- 25
0
votes
0
answers
5
views
Stuck during login on server - conda related?
When I am login to my server, the terminal halts and I have to hit CTRL+C to continue and entering the server. After hitting CTRL+C I get a lot of warnings (?) related to condo I believe. Any idea ...
- 153
1
vote
1
answer
37
views
bash looping over files while tailing logs
I'm running a daemon that process files in a specific dir.
I want to process those one by one. so idea is I will copy files 1 by 1 in daemon dir, and tail its log, 2nd file should be copied to daemon ...
- 1,703
0
votes
3
answers
45
views
Process the same stdin two time and append the outputs
I have a json file that looks like:
[
{
"key": "alt+down",
"command": "-editor.action.moveLinesDownAction",
"when": "...
- 1,329
4
votes
1
answer
36
views
zsh: pass variable by reference, and modify its value (like bash's local -n namerefs)?
Is it possible to pass a variable to a zsh function, and modify its value without using eval? I came across a bash way to do that: local -n: https://stackoverflow.com/a/50281697
- 254
1
vote
2
answers
34
views
Script to find all empty git repositories on a machine
We know an empty git repository only has the .git directory in it.
I want to find all git repositories on a machine, which are empty.
I thought about this process:
Find all directories that are named ...
- 249
1
vote
1
answer
25
views
capsh works but systemd doesn't - Openvpn unprivileged user
OS: Debian 11
Package: OpenVPN 2.5.1
Background:
After an update, Openvpn-2.5 clients can no longer use iproute to
modify the interface and configure routes pushed by the OpenVPN server
after root ...
- 87
0
votes
3
answers
67
views
Better way to convert IP?
I am trying to convert 10.AB.C9.XYZ to 10.AB.C2.252.
Right now I am extracting each character and piecing them together.
ip_main=10.AB.C9.XYZ
A_char=${ip_main:3:1}
B_char=${ip_main:4:1}
C_char=${...
- 323
0
votes
1
answer
39
views
Possible to match multiple conditions in one case statement and pass them as variables?
I have a bash script where I want to set a case variable. For file1 there are two different NUMBER variables that I then I want to pass to a text file.
I have tried the following:
case $FILE in
&...
- 1
0
votes
0
answers
19
views
Use of makefile varriable in Batch script [closed]
I have a variable in my makefile (mybuild.mak).
The makefile has a variable. i.e
BUILD_PATH = D:/<some path>
The variable BUILD_PATH is to be used in a batch file (RunTest.bat).
How to use the ...
0
votes
2
answers
34
views
How to correctly line break and concatenate a string in a bash script
I have a Bash script with a function to log messages with time and status, and I want to keep my script 80 column only:
#!/bin/bash
log_message() {
echo "[$(date)]-[$1] : $2" >> log....
- 593
4
votes
5
answers
335
views
Finding the line number of first occurrence of a text in bash script
I need to find out what is the line number of first occurrence of a given search string that should be in the start of a line in a text file and store it in a variable in my bash script. For example I ...
- 593
1
vote
2
answers
23
views
substitute 2 substrings from a single line in a file into 2 different lines in a different file from command line
I have a text file with however many lines. One line is:
fixed_stringA = 123, fixed_stringB = 456
I have a second text file (again with however many lines). These 2 lines are in this order, in middle ...
- 111
0
votes
0
answers
40
views
mv throw error when executed in shell script
OS: Ubuntu
I have the folder testfolder/subfolder with content
backup
file1.txt
file2.txt
testFolder
And I have script testfolder/testMv.sh
Now I'm inside of the bash session and do the following:
...
0
votes
1
answer
32
views
How to elude using eval set -- for parsing arguments?
While studying the parsing of arguments by bash scripts using getopt, I have almost everywhere watched the use of this construction: eval set -- "$SOMETHING_PARSED". For example, here and ...
- 103
1
vote
0
answers
64
views
Shell script does not run at desktop startup
I have a simple script that I want to run at startup but it doesn't get run.
The script is simple, it just swaps right Option key with right CMD key on my Apple Magic Keyboard:
#!/bin/bash
xmodmap -e &...
- 371
0
votes
1
answer
70
views
What does backticks do when in beginning of line in a bash script
I have noticed a weird behavior when a backtick is used in the beginning of line in bash scripts.
example 1:
echo "Test"
`ls`
Output:
Test
and ls is ignored.
example 2:
`test ':";`|)...
0
votes
2
answers
30
views
Get value from a key value pair separated with pipe
I have a string as below
Delete :xna.del|mode:Full|Execution: loaded
I need my output to be stored in 3 parameters.
for an example
a=xna.del
b=Full
c=loaded
