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.
24,071
questions
0
votes
1
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17
views
How to use pipe with "sudo -ui"?
I have this command
cat ~/.ssh/id_dsa.pub | ssh root@[my_server] "cat >> ~/.ssh/authorized_keys"
How can I do the same thing but with "sudo -iu user1" before the 2nd cat? ...
- 13
1
vote
2
answers
35
views
How to merge data from multiple background jobs back to a single data stream in bash
I've run into a couple of similar situations where I can break a single-core bound task up into multiple parts and run each part as separate job in bash to parallelize it, but I struggle with ...
- 37
0
votes
1
answer
44
views
How to simplify output redirection command line?
I have frequently used output redirection commands in my Linux environment, for example,
echo mymodule set number 10 >/proc/aaaa/bbbb_cmd
And I want to omit the echo .... >.... and use this ...
- 9
0
votes
1
answer
38
views
Bash alias with a loop, a sudo, pipes, flags, single quotes and double quotes
I want to make a bash alias of the following command, which works typed out on the command line but all my attempts at making an alias have failed. My only diagnosis is that all those nested quotes ...
0
votes
1
answer
24
views
unable to print a positional parameter in a script
I'm using this method to open a Gnome terminal window and run command(s) — in this case, to send me simple notification messages (will be scheduled via at):
#!/bin/sh
gnome-terminal -- /bin/sh -c '...
- 244
1
vote
1
answer
59
views
How to preserve parameter expansion passed to a function?
I have this function:
cyan=`tput setaf 6`
reset=`tput sgr0`
function Info()
{
echo "${cyan}$1${reset}"
}
And I use it in my other scripts as simple as Info some message.
However, when I ...
- 217
1
vote
1
answer
54
views
How to append to an array with a dynamic variable name?
section_example=(one two three)
name=example; section_$name+=(four)
bash: syntax error near unexpected token `four'
Section names are unknown beforehand. eval and declare -a output the same error. ...
- 142
0
votes
1
answer
22
views
Using expect in bash to execute a command with a password request
I have worked for a while on making a BASH script to go through two lists and creating a command out of it.
In the end it should execute the command and synchronize my ZFS server and ZFS backup server....
- 43
-1
votes
0
answers
46
views
Alpine ash seems to have trouble with a "while; do ...; done that bash is fine with [duplicate]
I was looking at the following, which I needed: Prepending a timestamp to each line of output from a command . I'm not using the accepted answer, I'm using the POSIX solution described in one of the ...
- 729
0
votes
0
answers
20
views
Bash's nullglob breaking variable assignments in source'd function definitions
So I've gone a little loopy tracking this problem down. I have a workaround, but it's ugly and I'd appreciate some better solution.
There's a Giant Pile of Automatically-Generated Shell Scripts that ...
- 103
2
votes
1
answer
25
views
modify group for one command
I want to execute one command and I want that it is executed with a specific groupname, that I'm belonging to, but which is not my default group. So all files created will belong to that group.
Is ...
- 123
0
votes
0
answers
26
views
Read string from file and pass to command, keeping dollar sign intact
Consider a string stored in a file, which I need to read and pass to a Node script via NPM. But the string in the file contains a $, and is being interpreted as a variable and is replaced before being ...
- 243
0
votes
0
answers
13
views
Systemd Service Java/Bash Script
I wish to create a custom service to start/stop a java process.
There already exists a start.sh/stop.sh for this java program.
sh-4.2$ cat /mnt/crx/publish/start.sh
#!/bin/bash
if pgrep -x java >/...
- 1
0
votes
1
answer
25
views
String compare negating in bash doesn't behave as it should be?
I have this little bash script:
readonly imagick_extension=$(cat "${php_configuration_file}" | grep imagick)
echo "Imagick extension grep value: $imagick_extension"
if [ "${...
- 103
0
votes
1
answer
42
views
How can I batch rename files by combining three variables and ignore file extensions?
I'm trying to create a script that renames a group of files. Normally they will be TIFs but sometimes an occasional oddball could be thrown in so I would like to rename the file and ignore the file ...
0
votes
2
answers
58
views
Change text using bash
I have a program called gamemode, and to check if it's running, you can use gamemode -s, which outputs either "gamemode is active" or "gamemode is inactive".
I want to change "...
- 1
1
vote
1
answer
50
views
How to use find and sed to replace certain sentences in files
I am using find and sed commands to find and replaces the occurrences of certain sentences in the whole directory with some other sentences.
For example if I want to replace all occurrences of the ...
- 167
1
vote
0
answers
32
views
Change the printed memory usage from dot to comma and then calculate the memory usage in %
So far, in a previously asked question: Calculate the real memory usage (memtotal - memfree - cached - bufferd) with /proc/meminfo one-liner
With many thanks to @Philippos this command prints the ...
- 21
1
vote
0
answers
10
views
define hierarchy of history files for ZSH
My zsh syncs history across terminals. Sometimes this is useful. But many times I just need the last command ran on a specific terminal.
So I'd like to have two history files in use by each terminal ...
- 111
1
vote
1
answer
64
views
Extracting text with expressions from a text file using grep
I have the following 2 lines in my text file and wanted to calculate duration between those lines X & Y in minutes.
line X: 18.05.2022 13:54:52 [ INFO]: Starting Component 'OWN_FUNDS_RULES' (5/15)...
- 125
5
votes
2
answers
470
views
Different behavior between SSH into VM and running SSH commands from script
I'm relatively new to shell scripting, so I apologize if this seems like a simple question to ask. I have a linux VM (debian, version 11 (bullseye)) that I can ssh into (ssh <ip>), installed a ...
- 53
2
votes
1
answer
56
views
Command '“export' not found when starting a terminal app in Ubuntu
Every time I start my terminal I get this message; how to get rid of it?
Command '“export' not found, did you mean:
command 'mexport' from deb mblaze (0.6-1)
Try: sudo apt install <deb name>
1
vote
1
answer
38
views
Delete folders from a directory once it's sbatch`ed in a for loop?
I am running a command using sbatch for a tool on the server, that takes a lot of space. The command uses some directories (some files) from a main directory(tq_first) in a for loop. I was wondering ...
- 13
1
vote
1
answer
15
views
Filter rows of a huge csv file based on values in 2 columns
I have a .csv files as shown below:
RepDate;FOO1;ProcessId;ClusterName;ProcessType
19700101;-1;Job_1000969943637142044;PROD;auswertung.mpeTestPlayer.xml
20181231;root;Job_107953405843118835;PROD;...
- 125
0
votes
2
answers
44
views
modify umask of a running process
I have a program, which can be used by a group and thus the output should have group writing permission by default, thus umask 002. Of course each user could do (umask 002 && cmd).
But since ...
- 123
0
votes
1
answer
27
views
inotifywait not detecting new directories
The script below watches for close_write events in the TARGET directory and does something with the file
#!/bin/bash
TARGET=/home/*/ftp/files
inotifywait -m -r -e close_write $TARGET |
while ...
0
votes
1
answer
29
views
How to merge and sort two shell variables, removing duplicates
In my bash script, I'm going to have two variables called "args1" and "args2". Each one of them is going to have content like this:
Matching cluster names:
[a-z]+
[a-z]+
...
So &...
- 729
0
votes
0
answers
35
views
change the bash output with stream editing [duplicate]
If I call bash like this: bash|sed 's/a/b/g' every time bash outputs an 'a' it is replaced with a 'b'
$ bash|sed 's/a/b/g'
$ echo aaa
bbb
$ exit
However if I add additional substitutions like so:
...
- 54
2
votes
0
answers
41
views
How to find (and move) all duplicate file names
Due to moving files back and forth from my Linux PC to a Mac, I now have a few documents that duplicate. Their names seem identical, but apparently they are codified slightly differently, like in this ...
- 121
0
votes
2
answers
34
views
Define bash function and chain `script` with it in a shell script
I am having issues defining a bash function inside a bash script and getting to use it in the same script when I try to chaining it after the script command.
A minimal working example is this. I have ...
- 103
2
votes
1
answer
141
views
How to properly use quotes for a bash function?
I am trying to define the following bash function in my .bashrc file:
function myfind() {
find $1 -not -path venv -not -path .tox -name "$2" | xargs grep -n "$3"
}
which is ...
- 5,162
-1
votes
1
answer
31
views
-bash: syntax error near unexpected token `(' when using lookahead and lookback?
The use case is rather simple. I have a text file, say the following named eg.txt:
'simple_example': 345, 'to_demonstrate': 232,
'regex': 'is not easy to use'
I am trying to capture the keys:
grep -...
- 101
1
vote
1
answer
26
views
How to automate the process to open 3 shells and run 3 commands?
I set up something so that I'd open up 3 shells and run the programs one by one:
cd foo/bar
./foo.sh
cd foo/bar
node bar.js
cd foo/bar
ruby foobar.rb
However, since it is time consuming, so I wrote ...
- 111
2
votes
2
answers
40
views
Setting time zone in a kindle bash file
I've recently jailbreaked my kindle to make it a clock that shows a certain image for each minute of the day. I used the instructions mentioned in this article
https://www.instructables.com/Literary-...
5
votes
4
answers
712
views
Shellcheck approved way to pass 2 arguments in one variable, to a command in a bash script
In a bash script, I call another programme, but I want to configure that programme with a command line option. The following works:
AREA_ARG=""
if __SOME_SETTING__ ; then
AREA_ARG=" --...
- 1,049
0
votes
1
answer
21
views
How can I extract multiple tgz files into seperate folder which have part of file names?
In linux bash shell, my files are listed like below:
xyz_a.tgz xyz_b.tgz xyz_c.tgz
and I want to extract each file into separate folder,
a b c
I tried like this:
$ for file in xyz_*.tgz ;...
- 3
2
votes
2
answers
83
views
Replace matched regex in file content with variables
I would like to do the following
Search file content with pattern (^[ \t]*services:[ \t]*)
If found, replace the pattern by a String (in variable)
Else, append the String (in variable) at end of file
...
- 123
1
vote
0
answers
87
views
TAB completion not working for mounted partition
I'm used to mount a Windows partition (G) into my Windows Subsystem for Linux (running Ubuntu 20.04) by giving the following commands:
sudo mkdir /mnt/g
sudo mount -t drvfs G: /mnt/g
Unfortunately, ...
- 23
0
votes
1
answer
24
views
Change prompt colour inside midnight commander?
I use mc on CentOS9. It has its own prompt on the bottom under the panels. I dont know if it is a separate bash or some sort of emulation, but it has default colour while "normal" prompt is ...
- 119
4
votes
2
answers
506
views
Bash script segmentation fault
My assignment is to write a bash script that reads a directory and returns the file type of each file within, including all subdirectories. Using the find command is not allowed. I've tried to ...
2
votes
2
answers
44
views
Remove files except latest one by numeric order
I am trying to remove files within a bash script.
I can list the latest file with :
ls | grep core | tail -n 1
and rename it like "keep-core-2994-xyz.bin", then remove the rest with:
rm -f ...
- 119
2
votes
2
answers
106
views
Replicating floating point arithmetic WITHOUT bc utility
I'm needing to write a script on some embedded Linux systems that don't have bc installed on them and won't be able to have it installed. The script I'm writing is essentially a monitoring script that ...
- 23
0
votes
0
answers
13
views
bash process icon changed since I ran celeste with it
I set a menu entry for launching celeste via bash and now the bash process in the gnome system monitor has celeste's icon even though I already closed the game. Launching another app this way or ...
- 1
-1
votes
0
answers
12
views
How to setup email alerts on centos when openconnect user connect
My current setup i have ocserv openconnect and postfix server running on centos 8
I wan get email alert when openconnect VPN user connected or disconnect .
2
votes
2
answers
183
views
How to add a letter in front of file names in a dir when file names have digit(s) at the beginning
I have a bunch of SVG files in a dir.
0.svg
1.svg
2.svg ...
42Group.svg
500px.svg
file1.svg
file2.svg ...
I'd like to add a letter A if a file name starts with a number.
For example, I'd like to ...
- 599
-5
votes
1
answer
57
views
What will this command output?
Can someone please explain in detail what the following bash command will output:
for i in $(du -kx / | tr -s "\t"""| cut -d""-f2); do echo $i | rev | cut -d"/"-...
0
votes
1
answer
30
views
Compare a file with stdout and print out not match line
Compare file.txt
cat file.txt
apache2 php7.4 mysql-server
to the output of
dpkg --get-selections
Any package that are not matched the content of file.txt, paste them as the argument of "apt ...
- 1
0
votes
0
answers
18
views
How can I redirect functions from a sourced file to individual scripts?
First I tried grepping the file using the matching only option and adjust from there;
# REGEX
function () { # ((\w|ç|Ç|ñ|Ñ)+\s+\(\)\s+\{\n)
blahblah # (.*\n)+
} ...
- 93
0
votes
2
answers
36
views
What's a clean way to run a specific command C for each line L of a given file F and then move every L where C(L) ran unsuccesfully?
Say that
https://example.nosuchtld
https://example.net
https://example.org
https://example.willfail
is the content of urls.txt. I want to run <command> <url> for every URL/line of urls....
-2
votes
0
answers
70
views
A script that terminates all processes owned by the current user, that have used more than 1 minute CPU time
How would I write a script that terminates all processes owned by the current user whose machine time (TIME column in ps output, which I believe is the CPU time) is greater than 1 minute?
- 17