Questions tagged [shell]
A shell is software that lets users interact with the operating system, usually by typing at a command-line.
4,060
questions
43
votes
3
answers
19k
views
How can I prevent tmux exiting with Ctrl-d?
I use tmux on my server and recently I found to my cost that ctrl-d will exit tmux and lose all the session information, my intention was to simply end the ssh session but failed to notice I was still ...
- 1,808
43
votes
4
answers
33k
views
Bash Shebang for dummies?
I have some bash scripts I have setup that mostly use
#!/bin/bash
but I regularly come across some that look like
#!/bin/bash -e
#!/bin/bash -x
#!/bin/bash -ex
and so on.
Can someone explain the ...
- 575
43
votes
2
answers
9k
views
Why does ‘tmux’ create new windows as login shells by default?
When you start a new session in tmux or create a new window inside a running session, its default behavior is to run a shell (ex.: bash) as a "login shell".
I understand that a login shell ...
- 583
42
votes
5
answers
228k
views
How to test if a variable is equal to a number in shell
I have this shell script that isn't working.
Input:
Server_Name=1
if [ $Server_Name=1 ]; then
echo Server Name is 1
else
echo Server Name is not 1
fi
Output:
Server Name is 1
But, if i ...
- 596
42
votes
9
answers
85k
views
Linux Shell: Copy output into clipboard w/o using the Mouse?
Is it possible to copy the output into the clipboard without using the mouse?
For example, I would like to do something like this:
$ pwd >> clipboard
- 1,985
41
votes
5
answers
5k
views
Can ',,' be aliased to '..'?
Sometimes when I want to change to the parent directory, I mistakenly type cd ,, instead of cd ... Is there a way I can make bash consider these statements to be the same? I never use commas in my ...
- 640
40
votes
2
answers
17k
views
Putty SSH: CTRL+Cursor keys don't work skip to previous/next word
When I am connected to my local Ubuntu dev server with putty (from my Windows 7 box) via SSH, the following key combinations don't work to move the cursor forward and backward on word boundaries:
...
- 611
40
votes
8
answers
64k
views
Why can't I highlight text in a linux terminal emulator with shift+arrow keys?
These are the standard text editing keyboard shortcuts that I use constantly whenever editing text in, literally, any linux application other than terminal emulators:
←+→ arrows to move left+right
...
- 591
39
votes
6
answers
114k
views
How do I rename files with spaces using the Linux shell?
I named a number of files with spaces in them, and I want to replace the space with _. However, every time I write a command in the shell with the file name (eg Spring 2011), the shell doesn't ...
- 531
38
votes
5
answers
13k
views
Deleting millions of files
I had a dir fill up with millions of gif images. Too many for rm command.
I have been trying the find command like this:
find . -name "*.gif" -print0 | xargs -0 rm
Problem is, it bogs down my ...
- 481
38
votes
3
answers
57k
views
How do I fork a process that doesn't die when shell exits?
If I run emacs from the shell:
$ emacs foo &
and then kill that shell, emacs dies.
How can I run a command so that it will not die when the shell dies?
I found references to nohup, but that ...
- 878
38
votes
5
answers
10k
views
Does running commands verbosely make them slower?
I've found myself using the -v flag for lots of applications less and less (especially for trivial stuff like tar and cp). However, when I did and I was, say, unzipping a large file, it would take ...
- 16.7k
37
votes
4
answers
28k
views
How do I change a users default shell in OSX?
What is the correct OSX way of changing a users default shell? When I googled for it I found several references to an application called NetInfo Manager but I couldn't find it on my system. There were ...
- 881
37
votes
3
answers
40k
views
How to remove shell integration of Notepad++?
I want to remove Notepad++'s annoying shell integration when right-clicking a file in Windows.
How do I do that?
- 6,461
37
votes
3
answers
157k
views
how to set ENV variable in windows CMD line
I'd like to set a temporary enviroment variable in windows CMD line, which in my word the windows shell. because it's for temporary usage, So I don't want to add a new enviroment variable system wise ...
- 4,027
37
votes
11
answers
37k
views
How do I copy file named starting with a dot?
I am trying to copy all files under directory A to directory B. All files under directory A are starting with dot, for example:
A/.a
A/.b
A/.c
which I found if I use: cp A/* B, always get error:
cp:...
- 505
37
votes
6
answers
123k
views
Windows & Git Bash: Bash PATH to read Windows %PATH% system variable
I've recently added a directory to the Windows PATH manually by going into Control Panel -> System -> Advanced system settings -> Environment Variables -> User variables -> PATH. (...
- 869
36
votes
5
answers
53k
views
How to cut a file to a given size under Linux?
I want to shrink a file's size by brute-force, that is, I don't care about the rest, I just want to cut the file, say by half, and discard the rest.
The first thing that comes to mind is Perl's ...
- 8,681
36
votes
5
answers
31k
views
How to change the default shell in Cygwin?
I am trying to change my default shell from bash to zsh in cygwin.
The normal unix command chsh isn't available on cygwin
The etc/passwd file it seems isn't used anymore in existing versions of ...
- 441
36
votes
2
answers
73k
views
how to bring a background job to foreground
in Linux/shell, how can I bring background jobs to foreground and vice versa?
- 461
36
votes
7
answers
41k
views
Stop Windows 7 Explorer from automatically expanding folders
Windows 7 Explorer can be opened in any folder from the command line. But, it automatically expands (on the left nav panel) the Favorites, Desktop, and [Username] folders. This makes it hard to see ...
- 361
36
votes
5
answers
25k
views
Bash/ZSH: Undoing 'disown'
Is there a way to 'reattach' a process to the shells job table after it it has been 'disowned'?
Edit: $SEARCHENGINE totally fails me. Doesn't look too good.
- 1,112
36
votes
2
answers
33k
views
Shell SIGKILL Keybinding
How can I setup a keybinding to send a SIGKILL to the current foreground job?
I already know that Ctrl+C is SIGINT and Ctrl+\ is SIGQUIT. I would like a more severe option.
Is there anything ...
- 881
35
votes
7
answers
37k
views
35
votes
4
answers
89k
views
How to change proxy setting using Command line in Mac OS?
I am using Mac OS and sometimes some work need to be done using a proxy so I need to change my proxy setting frequently. But changing proxy setting in System Preferences is very messy.
Is there a ...
- 353
35
votes
2
answers
1k
views
How do I teach my linux command line manners?
Whenever I complete something in the command line while using Ubuntu and my computer does something of value to me, I enjoy saying thank you, just because it's the polite thing to do. A typical ...
- 2,182
34
votes
6
answers
12k
views
What zsh features do you use? [closed]
I do a lot of work in the terminal so I have learned a lot about my shell of choice, zsh. What features of zsh do you use to make yourself that much more productive at work? One of my favorites is ...
- 1,261
34
votes
4
answers
36k
views
Why is the size of a directory always 4096 bytes in unix?
I am sure a directory file has much less information than 4096 bytes. I know the sector size is 4096 bytes. But normal files smaller than that do exist.
Why does Unix reserve 4096 bytes for each ...
- 17.7k
33
votes
4
answers
13k
views
ZSH tab completion of git commands is very slow. How can I turn it off?
If I type:
rm <TAB>
I'll see possible completions almost instantly.
However, if I type:
git rm <TAB>
It'll hang for several seconds if it's in a git repo, or fail to show any ...
- 432
33
votes
7
answers
29k
views
How to "undo" unzip command?
I used "unzip XXX.zip" to extract a zip file, unfortunaly, i make a mistake.
Now i want to delete all the file and directorys generated by "unzip".
How can I undo it?
- 637
33
votes
2
answers
155k
views
Shell script echo new line to file
I want to echo a new line to a file in between variables in a shell script. Here's my code:
var1="Hello"
var2="World!"
logwrite="$var1 [Here's where I want to insert a new line] $var2
echo "$logwrite"...
- 1,639
33
votes
2
answers
148k
views
HOSTNAME environment variable on Linux
On my Linux box (Gentoo Linux 2.6.31 to be specific) I have noticed that the HOSTNAME environment variable is available in my shell, but not in scripts. For example,
$ echo $HOSTNAME
returns
...
user34614
33
votes
2
answers
125k
views
What is the right way to set the $PATH variable in .zshrc
When I first installed Zsh (using Oh My Zsh), the ~/.zshrc file had the following commented lines by default:
# If you come from bash you might have to change your $PATH.
# export PATH=$HOME/bin:/usr/...
- 450
32
votes
5
answers
26k
views
Aliases in subshell / child process
I set up aliases in /etc/profile.d/alias.sh for each login shell. But if I run script.sh, I can't use that alias. How can I set alias even for subshells or child processes ?
/etc/profile.d/alias.sh
...
- 455
32
votes
4
answers
10k
views
What does % do in Linux shell strings?
In Linux shell, what does % do, as in:
for file in *.png.jpg; do
mv "$file" "${file%.png.jpg}.jpg"
done
- 650
32
votes
2
answers
49k
views
How do i configure a Logitech G502 Spectrum under Linux?
I'm thinking about buying a Logitech G502 Spectrum (the G502 with RGB LEDs) but as I am running Linux (Speciified in Debian @ work, ubuntu @work and archlinux @home) I am woundering how to setup ...
- 486
31
votes
4
answers
76k
views
How do I find (and kill) process running on a certain port? [duplicate]
Possible Duplicate:
Finding the process that is using a certain port in Linux
I'm using Ubuntu Linux 11.04. How do I write a shell script expression that will find the process running on port ...
Dave
31
votes
11
answers
171k
views
Running scripts from another directory
Quite often, the script I want to execute is not located in my current working directory and I don't really want to leave it.
Is it a good practice to run scripts (BASH, Perl etc.) from another ...
- 2,600
31
votes
4
answers
11k
views
BASH history truncated to 500 lines on each login
For some reason, I cannot get my system to keep my BASH history after a reboot. Here are the relevant sections of my ~/.bashrc:
shopt -s histappend
PROMPT_COMMAND='history -a; updateWindowTitle'
...
- 53.4k
31
votes
5
answers
22k
views
How can I do Ctrl-Z and bg in one keypress to make process continue in background?
I follow this pattern of suspending the task and then letting it to continue too often with the Ctrl-Z bg sequence.
I was wondering is there any way to compress that to single keypress?
My shell is ...
- 481
31
votes
8
answers
120k
views
How do I run the Windows 7 Explorer shell with Administrator Privileges by default?
The Windows 7 shell (Explorer) can be made to run with Administrator privileges by this manual process:
Kill Explorer shell by holding down Shift+Ctrl, right-clicking the Shut down button in the ...
- 733
30
votes
9
answers
8k
views
30
votes
8
answers
9k
views
Is it possible to restart a computer in response to an email notification?
I'm looking for a way to reboot machines after getting an email notification.
The setup I want to use this on is a render farm. We have 5 boxes with 8 Nvidia GTX 980Ti in them. They're running ...
- 941
30
votes
6
answers
98k
views
Why run a Linux shell command with '&'?
I am using Red Hat Linux Enterprise version 5. I've noticed people sometimes running commands with a couple of & options. For example, in the below command, there are two & signs. What is the ...
- 5,049
30
votes
9
answers
25k
views
loading local shell aliases to ssh session dynamicaly
When I log in to some machine using ssh I wish my aliases and functions are there. In other words, log in to some machine I wish I can use my command shortcuts.
I need it be dynamic, every time I'm ...
- 661
30
votes
3
answers
73k
views
How to run pip in non-interactive mode?
Most of tools I'm using have some mode (often ON by default) where they ask me zero questions while running the command. apt-get is an example close to pip. There's -y option which makes it non-...
- 497
30
votes
3
answers
40k
views
What is the difference between CMD and Command prompt in windows?
Until now, I never thought (and never observed) that cmd and command are two different things. Well, are they?
Take a look at this pic:
Actually, I usually open cmd from the Run dialog whenever I ...
- 433
30
votes
1
answer
23k
views
ZSH Completion colors and OS X
Consider this minimal .zshrc :
export CLICOLOR=1;
export LSCOLORS=exfxcxdxbxegedabagacad; # It is the default value on OSX, so this line can be omitted
autoload -Uz compinit
compinit
zstyle ':...
Someone
29
votes
3
answers
23k
views
How do I make "find" exclude the folder it searches in?
I'm running the following command:
find /var/www/html/content/processing -type d -mtime +1 -exec rm -rf {} \;
I would like to delete all the folders under the processing folder (the processing ...
- 433
29
votes
3
answers
23k
views
Setting pipefail for a single piped command
I need to execute a number of piped shell commands from a non-BASH script (namely PHP script) like these:
command1 | command2 | command3
so that, if command1 fails with a non-zero exit code, each ...
- 2,600