Questions tagged [shell]
A shell is software that lets users interact with the operating system, usually by typing at a command-line.
4,057
questions
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What is the shell exactly when using Cmder on Windows?
I've just started using Cmder on Windows 7 and I understand that is a console emulator for Windows which gives a better experience than using cmd. However as I understand it the emulator needs to run ...
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1
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Antigen failing to load theme from .zshrc
I have a fresh Debin Bullseye installation and I can't get antigen to load a theme if loading it directly in .zshrc.
I installed zsh and zsh-antigen using apt.
My minimal .zshrc:
source /usr/share/zsh-...
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1
answer
329
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Shell appending unknown integer to hostname in prompt (zsh) on mac
I recently customized the prompt in my terminal to be more like the one from parrot os, which I really like. I have read over the documentation many times on how to use the markers/variables in the ...
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2
answers
1k
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How to understand what this sfdisk command is doing
In this command what is happening? I tried to know but what are these numbers and parameters 2048,,0x0C,-?
sfdisk -u S -L -q ${RAW_FILE} 2>/dev/null << EOF
2048,,0x0C,-
EOF
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1
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3k
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Passing variables to docker run from within a bash shell, getting "unterminated quoted string" error
I have a bash shell with multiple variables that form the command options of a docker run command. I suspect a < character is breaking the config line that I am passing.
This is the command that I ...
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1
answer
510
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-v unary conditional expression isn't working
I want to check if the given variable is set with the -v check. I'm struggling to understand where the error is coming from. Having the following script in a file var-test.sh:
MY_VAR="test"
...
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1
answer
114
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Understanding Operators in find command
[kony@HOSTNAME testing]$ pwd
/apps/kony/fmw/testing
[kony@HOSTNAME testing]$ touch SCCS
[kony@HOSTNAME testing]$ touch NOT_SCCS
[kony@HOSTNAME testing]$
[kony@HOSTNAME testing]$ find . -name SCCS -...
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1
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527
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How does exec interact with pipes in shells?
Assume I have the following in the beginning of my code:
exec < file
It means, if I understand correctly, that all commands trying to read from stdin will actually read from file.
But if I have ...
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1
answer
282
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loop through subdirectories and ffplay all mp3 files
hi i'm trying to iterate through subdirectories and ffplay all MP3s in subdirectories, but i keep having only one track playing after it stops, here is my code
#!/bin/bash
shopt -s globstar nullglob ...
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1
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397
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How do I count number of times that a command has ran and add if condition?
Basically I need to control how fast I upload files to AWS S3 - I have a folder with tens of thousands of files, and this is what I do now:
for f in *; do aws s3 cp $f s3://my-bucket; done;
What I'd ...
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1
answer
738
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Binding Alt-Shift-. in tmux
I'm trying to bind some key combinations in tmux, this is what I have in ~/.tmux.conf:
bind-key -n 'M-S-.' next-window
This doesn't work. How can I bind it?
I'm running Konsole in KDE Plasma, ...
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2
answers
2k
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Getting rid of "command not found..."
When I mistype command in terminal I got this error:
bash: XX: command not found...
After that, I have to wait or use keyboard interrupt before I can use prompt again.
Sometimes shell offers me to ...
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3
answers
805
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MacOS Terminal: Control+C "hijacked". Terminal outputs ^Z when I click Control+C
I seem to have a peculiar issue with MacOS Terminal (or iTerm) from time to time and I cannot pinpoint the cause.
Whenever I need to kill a program in Terminal, Control + C doesn't work. Terminal ...
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1
answer
1k
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How do I run tesseract (anything really, that requires write permissions, from a shell) on windows10?
I am trying to run tesseract on windows10 (home ed), but this question is really more generic.
Sources and instructions to run the program are here.
I am running a downloaded windows binary, not a ...
1
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2
answers
777
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How to list all files of a directory along with an index to allow users to choose file by inputting the index number?
I have multiple files in a directory and I am working on a bash script to list down all the files along with an index next to them so that the users can choose which file to select on the basis of the ...
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1
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85
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Simple if/elif/else bash program with READ
The following code always ends up in the else part - also if I enter "peter" or "root". I do not get a syntax error. What am I doing wrong?
#!/bin/bash
# Hello World bash script
echo "What is your ...
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1
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120
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Shell - Is *${i,,}* correct and what is it for?
I am reviewing a shell script and found this lines :
DIR=/home/bot/REP_INV/
LIST=/root/ListeTRI.txt
...
ligne=`cat $LIST`
for i in $ligne
do
/bin/cp $DIR*$i* /root/$i/InvExt/
/bin/cp $DIR*${...
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1
answer
2k
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handling of space and newline
Assuming user has 5 processes started, what is queried with below sentences:
cuser=`whoami`
a="`ps -C process -o user= | grep $cuser`"
echo $a
user user user user user
vs.
echo "`ps -C process -o ...
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1
answer
67
views
list of on-demand shell variables?
tl;dr where can I find a list of shell variables that are on-demand (not listed by env)
Variables like $OSTYPE or $COLUMNS (bash) or $RANDOM (bash) are not listed by env.
Where can I find the list ...
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1
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126
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Not able to run a command through ssh
I am running a command on a FreeBSD machine (xxx.yyy.zzz.net) and getting the output
command
sudo camcontrol devlist | grep -o 'ada[0-9]' | while read -r a ; do sudo camcontrol identify $a | grep ...
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2
answers
8k
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What's the different between 'cat > some_file << EOF some_stuff EOF' and 'echo "some_stuff" > some_file'
This is a question of knowledge respectively research.
I'm not quit clear why I should use this code:
cat > $FILE << EOF
command1 $var_this_routine
command2 \$var_attached_routine
...
EOF
...
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2
answers
2k
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Clear multi-line input in IPython
The current line on the IPython prompt can be cleared with the keyboard shortcut Ctrl-U. Is there any shortcut that clears all lines on the IPython prompt in one go?
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1
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76
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Move a range of numbered files and change their value
I've got numbered files (DSC_0001.jpg to DSC_0065.jpg), I know how to move them with mv DSC_{0001..0065}.jpg dir.
I have no idea how to move them and change the range of values.
mv DSC_{0001.....
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1
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304
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Move folders containing files with extension
Example folder structure:
➜ test tree
.
├── testflac1
│ ├── track1.flac
│ ├── track2.flac
│ └── track3.flac
├── testflac2
│ ├── track1.flac
│ ├── track2.flac
│ └── track3.flac
├── ...
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1
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221
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How to quit a non-login shell?
e.g. I use ssh to login into a Linux server with zsh. Then in the zsh, I type zsh to get a non-login shell. How can I quit the non-login zsh and get back to the login zsh?
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1
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122
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what is bash command `command` used for and what is it when it appears in shell script
when I was writing a shell script, I happen to know command is a reserved word. Then I noticed command is also a bash command.
command ls gives the same result as ls.
command ls | grep xxx gives the ...
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2
answers
795
views
Is it POSIX-compliant to use a shell function in a pipeline?
Is it possible to use a shell function in a pipeline?
Say I had a function that acted like grep, called mygrep.
Is there any way, using only POSIX shell features, to be able to invoke
mygrep like ...
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1
answer
73
views
How to extract multiple urls from String?
I have a string like below
https://website.com/BTAE/2015/BTAE assignment jan 15.pdf²0ÔË'\„QI„"ÙP¾^ŒŸZ‡@Æ*]Ü.^‚vðƒ€Ù¾»Æš©Šñ‘€é•
ªÂIR#œÉgÉÛ^gMdÉ%9¬e˜Hžôb¿'0<ô ?lþzk…éÃÄórÈ;EW¦K³1…²ì¶ZFžŠÒô*ÄÖ\...
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1
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859
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urban legend : why is it better to avoid using file descriptor 5?
In the answer to this question, the answerer quoted a block of scripts, which contains a line like this
exec 4>/path/to/output.file
#and a third, for reading and writing, with FD 6 (it's not ...
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1
answer
318
views
shell command on matching line (in vim: combine the global `:g` or `:v` command with shell command)
I want to use a shell command (fmt in this case) to operate on every (non-)matching line of a regex in a file. I'd prefer to do it within vim! I am, nonetheless, open for a pure shell/bash/zsh ...
1
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1
answer
2k
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can't increment a variable inside a loop in a bash script
I am running a bash script in Ubuntu 18.04. The script needs to run a python script 10 times. I did the following testbash.sh script:
#!/bin/sh
count=1
while [ $count -le 9 ]
do
python /home/e/...
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1
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832
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Bash: Copy a list of files that contain (lots of) special characters
I'm well aware of how to simply copy a list of files to another location using bash, but the problem is that my list of files contains filenames that contain just about EVERY character that needs to ...
1
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2
answers
1k
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Need to skip the HomeDirectory permission check on remote machine for the ssh client .How to set StrictModes off for a specific host in ssh client?
I am trying to connect to a remote machine over ssh in a passwordless manner using ssh-keys .But it is failing to connect without password due to the permission on the remote server home folder (777) ....
1
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1
answer
579
views
Encryption compatibility between TCL and openssl
I have a shell script and a tcl script using encryption mechanism and want to have a same cipher output from both the scripts.
for example, the output cipher of tcl script and shell script should be ...
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1
answer
51
views
less -z option: the manpage refers to it, but does not document it
Simply put, what does the -z flag to less do? In the prezto (zsh shell) config, the $LESS env var is set with flags and the last one is -z-4.
What does this do? Is there a version of a less manpage ...
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2
answers
30k
views
Execute Shell Commands from Excel Cell
I have a shell command, to execute a program with additional arguments.
Shell "C:\Program Files\uvnc bvba\UltraVnc\vncviewer" & " " & Range("$G3")
The cell G3 contains an IP address I wish ...
1
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1
answer
373
views
pass the result of command to another in batches
Lets say command1 results an array of 10000 value,
I want to pass this result to command2 in 20 patches, 500 value each.
What I have now
command1 arg $(command2 arg)
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Change color of hostname in Fish shell prompt
I'm migrating to a new Mac, and I'm having trouble setting up my shell to match the old one.
Old:
New:
Notice the host color is different? I copied the entire .config/fish folder over to the ...
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1
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1k
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What is '-f option' in zsh
I am trying to understand when is .zshenv source and in manual both in terminal and online is mentioned that
.zshenv is sourced on all invocations of the shell, unless the -f
option is set
...
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1
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2k
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Special characters in the shell
I know that some characters like " or * need to be escaped to mean its literal value.
I wonder if is there any definitive set/list of all of them?
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1
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1k
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Chatting using Bash Shell?
The origins of the questions trace back to Mr. Robot series, where I noticed that people join "group" or "parties" chat through Bash Shell to communicate with other people or group. Then I got ...
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1
answer
826
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Pipe in Environment variable in fish shell doesn't execute the first command?
I want to set fish_greeting to date --rfc-2822 | cowsay -f tux | lolcat (don't judge me). When I run date --rfc-2822 | cowsay -f tux | lolcat interactively, I get the proper output (the date in a ...
1
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1
answer
4k
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How to pass array to bash shell script?
How do I pass an array as a variable from a first bash shell script to a second script.
first.sh
#!/bin/bash
AR=('foo' 'bar' 'baz' 'bat')
sh second.sh "$AR" # foo
sh second.sh "${AR[@]}" # foo
...
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1
answer
1k
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Accessing array index variable from bash shell script loop
I want to access the array index variable while looping thru an array in my bash shell script.
myscript.sh
#!/bin/bash
AR=('foo' 'bar' 'baz' 'bat')
for i in ${AR[*]}; do
echo $i
done
The result ...
1
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1
answer
99
views
Access to line arguments in shell script
I wonder if there is possible to access full command line call in shell script. In my script I need to pass it further. I find that there are $@ and $* accessors, but it do not pass all the characters,...
1
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1
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2k
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Using shell (bash) to determine key for value from file
I am scripting some application deployment and deploy promotion processes using bash (shell). These scripts are being written as a failsafe in case our CI platform ever fails again (as it has recently)...
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1
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2k
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Changing sh color in .bashrc
I'm trying to change the color of my shell which I connect to using Putty.
When I type this
export PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h:\w\$ '
I get exactly what I want. ...
1
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2
answers
89
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Import previous commands to edited command
I'm playing with zsh to change image modification time according to the 'Date/Time Original' exif attribute.
For this I one command I do:
PDATE=$(exiftool -p '$DateTimeOriginal' $PIC | sed 's/[: ]//...
1
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1
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11k
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Terminal 'last' command doesn't display login history
The last command in Terminal (on Mac OS X 10.11.2) is supposed to display a list of login history. However, when I type it in, all I get is
user$ last
wtmp begins Mon Jan 11 13:17
user$ last user
...
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2
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9k
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How to get HTML file as a content to mail (shell script)
I am new to shell script, I have an HTML file which contains table data. Now I need to send this file to mail.
mail -s "test" abc.com <test.html
Currently I am getting the raw HTML code for the ...