A shell is software that lets users interact with the operating system, usually by typing at a command-line.

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24 views

Search for string and read the next line

I need to write a shell program that installs some packages. The program will run on Linux (obviously some commands will not work, for example, on Arch-based distros). So, I've got this file called ...
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49 views

processing sequential and parallel jobs in bash script

I understand that in bash programming, comamnd1;command2;command3 will run them sequentially while command1&&command2&&command3 will run them in parallel. However what happens when I ...
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15 views

How to revoke myself rights to write files outside current directory?

I want to make sure commands that I run from my shell cannot damage my files above starting directory. For example, this command should fail: cd ~/ && rm -rf *. Supporting links, mount points ...
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31 views

Indent execution results in zshell

I'd like to customize my zshell so that the prompt is butted up against the left border like normal. I'd also like to have all execution results indent by perhaps 2 spaces. Is there a way to indent ...
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2answers
30 views

Is there a man page for PROMPT in zsh?

I know how to look up commands with the man command. When looking at other people's .zshrc files, I see what I think are builtin variables (PROMPT, RPROMPT, etc.). Where might I learn more about ...
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96 views

How can I rename/move a file by simply “editing” its path in a shell?

Consider the problem that you want to rename a file called some/path/File With A Long Name.txt into some/path/File with a very long name.txt. To me, this was always one of the few situations, where ...
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56 views

In bash 4.3.27 “su” ignores user variables when combining “-” with “-c command”?

Since forever we used to launch user scripts from a different user crontab like this: 00 12 * * 1 su - user2 -c "/home/user2/myscript.sh" By doing this, the script is launched after the interactive ...
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33 views

How to show a caret-C in canceled command line in zsh, like bash does?

When I'm in the middle of entering a line to my shell of choice, and change my mind, I can quickly throw C-c and start afresh. Under bash it looks like this: user@machine:~$ rm everything^C ...
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22 views

ZSH custom widget not working as I think it should

I'm trying to define a function so that I can launch Midnight Commander by pressing Alt-, but the function just doesn't work. I found and modified a function on another site and modified it so: ...
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117 views

Script to automate copy files with a pattern over network

I am trying to automate some tasks... I have to do some development work on one machine and other parts on another machine, with communication through a network share. I would like to copy certain ...
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968 views

Prevent currently running linux task to be killed after logout from SSH

I have a computational task running for a few days on a linux server via SSH connection. It is not on the background, so the SSH connection is under hold of the task. I want to restart the local ...
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19 views

Running terminal command on all files in folder? [duplicate]

I need to convert 500+ .xlsx files to .txt (or .csv). To do this I found this. It works well if I write the command like this: xlsx2csv fileA.xlsx fileA.txt I have however been unable to run the ...
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38 views

Tar not preserving permissions on extract

I'm backing up a users folder as root using tar tar -czf /mnt/disk/cloud.tar.gz -C /home/cloud/ . In /mnt/disk I do a test tar ztvf cloud.tar.gz and it shows -rw-r--r-- cloud/cloud 14 ...
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89 views

ascii value in bash/awk

i have a doubt, i know that with this command, it prints the value of a character based on the Ascii table: printf "%d\n" "'a" ##prints 97 But i wonder how can i make my programm show me the ascii ...
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39 views

Where do the variables of a new BASH shell come from?

I am puzzled as about how environment variables work. From what I am aware, for a new process to have some environment variables, its parent must have issued export. But what about all the variables ...
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103 views

How to check if busybox has a command?

In my case, I want to see if busybox has "md5sum" builtin. I am currently doing this: $ echo | busybox md5sum &>/dev/null && echo yes || echo no I have not been able to find any ...
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2answers
57 views

Warning for rm -r command

I want rm to prompt me when recursively deleting a directory, as in: $ rm -r <dir> Do you want to remove the dir(Y/N)? Is there an argument I can pass to rm that will do this?
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172 views

Bash script that calls a program with some asterisks in arguments

I’ve spent last hour or so trying to write a pretty simple bash script and I never felt so dumb. So I have a list of strings (which are package selector specifications for a package manager, if that ...
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44 views

Passing different set of arguments to the different commands in a linux bash script

I am writing a bash script foo.sh that runs too commands bar with first input argument, and baz with the second argument: #! /bin/bash bar "$1" baz "$2" Now I want to make foo.sh more flexible, ...
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117 views

How to copy hidden (starting with a dot) files and subdirectories in linux?

How to copy hidden files and hidden subdirectories (the ones starting with a dot) in folder A to folder B? For example if I have this structure: A/a A/b A/.a A/.b/ A/.b/somefile A/.b/.c I would ...
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49 views

OpenWrt Script (Inifinite Loop) Stops sending data over Serial Port

I have a TP Link Router TL-MR3020 flashed with the latest Attitude Adjustment. It is connected to an Arduino Uno via the usb port (usb cable into the arduino's type b connector). I have the following ...
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22 views

In bash, declare an alias that depends on current variable content

I would like to declare an alias in my .bash_profile that will use the content of a variable when the alias is used and not when it is declared. Ex: alias goSomeWhere="cd $BASE/somewhere" When ...
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43 views

modify shell command in Ubuntu 14.04

I had installed Ubuntu 14.04 on virtualbox, I need to be able to read source code of shell commands, and modify any command? any help please? where i can find the shell commands? in which directory?
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31 views

Kill browser tabs with Bash from younger to older

Hello i want to kill tabs from a browser(ex. chromium) by order from youngest to oldest. I used pkill -f -n -9 chromium but i want to use it in a while iteration with comparison to pkill's return ...
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95 views

What is the difference between “elif” and “else if” in shell scripting?

I am very new to shell scripting. When I look at some code, written for ksh (#!/bin/ksh) I see there is else if as well as elif used in one script. So, what is the difference between else if and ...
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37 views

Alter output of every command

I'd like to know if there's any way of altering output of every command I execute in terminal. The purpose is to make the output formated for my markdown howto's. E.g. ls -la .*z #>-rw-r--r-- 1 ...
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97 views

echo “something” > file not working when sh script is being executed by remote PHP server

I've got a web-server with my hardcoded webpanel for Source server management and I've got my VPS on CentOS which doesn't really want to execute sh script when asked from remote server. Web-server ...
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1answer
41 views

Good way to bookmark/navigate relative directory paths?

I work on a linux system with bash 4.x where I frequently find myself navigating different copies of very deep (and large) file directory structures. However, in reality I only need to access a ...
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2answers
197 views

Why is “source <(cmd)” working but not “$(cmd)”

I want to have a script to call with params which adds some aliases to my current shell. The aliases have to be builded in respect to the calling parameters and the current directory from where I ...
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1answer
78 views

Split very long line of words into separate lines of max length

I have a script that outputs a list of packages on a single long line separated by spaces. The information included in this line shall be inserted into a text file which is later presented to a user. ...
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1answer
255 views

Percent sign (%) in front of shell command

I just pasted a bunch of code into my shell, but forgot to remove the leading % before running the command. It appears to have done nothing. Why does this do nothing in my shell (zsh)? > % echo ...
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104 views

Linux find files in subdirectories by extension (.txz) then move them to specified directory using regular expressions [duplicate]

I have mirrored a directory from a server with a large number of sub directories, each of which contain a .txz package and the usual .txt and descriptor files. What I would like to do is the ...
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7k views

Is “ps -u” Really a Bad Syntax?

IMHO ps -u shows a very useful output, much better than ps -u $USER: $ ps -u Warning: bad syntax, perhaps a bogus '-'? See /usr/share/doc/procps-3.2.8/FAQ USER PID %CPU %MEM VSZ RSS TTY ...
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1answer
59 views

output of sudo -l confusing me

(habdbsync) NOPASSWD: ALL, (habdbsync) !/bin/sh, !/bin/ksh, !/bin/csh, !/bin/tcsh, !/bin/zsh, !/bin/bash, (habdbsync) !/bin/su, (habdbsync) !/usr/bin/ssh, !/usr/bin/scp, !/usr/bin/slogin (root) ...
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577 views

How to justify and center text in bash?

Newbie here. I'm looking for bash script to center and justify text. My script only works with one line of text. How would you improve it? #!/bin/bash COLS=$(tput cols) while true; do clear ...
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2answers
227 views

How to take control back on a separate process in Linux shell?

I just set up a Minecraft server on my VPS for my brother and I ran it with a bash script : sh ./server.sh& This way, the server is running and I can still work on the same command line with ...
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58 views

UEFI shell mode with no colon key

I have a newly built PC with a UEFI-enabled motherboard and I'm having trouble getting my DVD drive to boot into UEFI mode so I opted to boot into UEFI Shell to manually start the DVD in UEFI mode. ...
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100 views

Unexpected Bash glob completion uses first match even if ambiguous

If I have the following files in a directory: $ ls a-file-1 b-file-2 something-else And I type $ cat *file*<TAB> The line unexpectedly updates to $ cat a-file-1 | (pipe denotes cursor) ...
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15 views

How can I open a file with its associated default application from a networked drive via Shell on Windows?

I have a file Z:\test.txt. I can do "notepad z:\test.txt". But "start z:\test.txt" or just "z:\test.txt" gives me "Access denied". I have full read/write access to the share. How can I fix or work ...
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2answers
75 views

Grep in newest file

I'm trying to find a specific line from the newest file I have in subfolders. Files have the same name. So structure is like: Folder SubFolder1 filename.xml SubFolder2 filename.xml I'm ...
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1k views

FileZilla: Can I run a remote shell command via FileZilla client?

I have a very simple question. Can I run a remote shell command on the server via FileZilla client. For instance can I do a: tar -zxvf myarchive.tar.gz etc... (didn't think it was possible with ...
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137 views

Shell Script automatically exits from SSH section after switching of user (through pbrun command)

I have the below piece of code.. ssh some_user@server << EOF echo 'Successfully connected to the server' pbrun previlige -u user ls pwd id ...few more commands EOF if [ $? -eq 0 ] then echo ...
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24 views

What does ${file?my.file.txt} and ${file:?my.file.txt} mean in Bash?

When I read some tutorial today, I came over with the statements like ${file?my.file.txt} and ${file:?my.file.txt}, what do ${file?my.file.txt} and ${file:?my.file.txt} mean in Bash script?
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149 views

What is the difference between set, env, declare and export when setting a variable in Linux shell?

What is the difference between set, env, declare and export when setting a variable in Linux shell, like Bash?
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59 views

Why variables in shell are not inherited by sub-shell now that the sub-shell is implemented by fork?

When running shell command in shell scripts, a sub shell process is generated. Doesn't the process is generated by fork function? Why the variables that are not exported are not inherited? In fork, ...
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66 views

Bash parameter Expansion: Best practices for speed?

I was just wondering if anybody knows any best practices or if there is any documentation about this topic: The scenario is searching / grepping in the log files. To make my point I will use ls. So ...
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54 views

Linux hosting with web-based shell access

I am looking for a service that gives user some computing resources, a Linux OS and a preferably web browser based shell access. Are there any services that you can recommend? The bandwidth usage ...
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20 views

How do I recover from a `tmux a` by mistake within a tmux session?

I have a tmux session with a pair of windows. I want to recover the stdout from both those windows. I found this example, and so, within my existing attached session, ran tmux a. I now have a screen ...
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19 views

List folders by modification time of children in linux?

I have a folder, we'll call it /scripts/, that contains subfolders for a number of different scripts (let's say /scripts/file_export, /scripts/record_ingest, /scripts/stats). Inside these folders are ...
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42 views

Change puTTy presets via registry

I am fixing presets through the .reg file instead of in puTTy because I am going to make this an open source registry. Mostly changing themes, and my school doesn't know what the hell they are doing ...