Questions tagged [shell]
The shell is Unix's command-line interface. You can type commands in a shell interactively, or write scripts to automate tasks. Use this tag for questions applying to /bin/sh and most compatible shells (ash, bash, ksh, zsh, …). For shell scripts with errors, please check them in http://shellcheck.net before posting here.
11,989
questions
778
votes
5
answers
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Difference between nohup, disown and &
What are the differences between
$ nohup foo
and
$ foo &
and
$ foo &
$ disown
- 27.2k
1
vote
1
answer
590
views
CH3MNAS Fun Plug and NZBget. Cannot launch NzbGet 0.7, word unexpected
I have un-tarred the nzbget0.70 debug version and have put it in the /ffp/bin dir. and I have a config file in the /ffp/etc/ dir
but when I try to run it, I get the following:
root@NAS:/mnt/HD_a2/...
- 113
142
votes
6
answers
165k
views
How to pass parameters to an alias?
For bash script, I can use "$@" to access arguments. What's the equivalent when I use an alias?
- 8,488
3
votes
2
answers
3k
views
Forcing emacs to run with `-nw` when called from terminal
note: This question might have been asked before ( I think I saw it somewhere), but a quick search did not reveal anything.
I would like to tell the difference when a command is run from a shell.
...
- 25.1k
6
votes
3
answers
3k
views
Deleting lots of files
I accidentally created 8 million files and every time I'm trying to delete them the server almost dies because of the rm process eating all disk IO (the server is remote without console).
Should ...
- 689
49
votes
2
answers
72k
views
How do I delete all files with a given name in all subdirectories?
I want to delete all files with a given name in all the subdirectories of my home directory.
I tried:
rm -r file
in my home directory, but it didn't work because that file doesn't exist in that ...
- 2,325
5
votes
2
answers
8k
views
Why am I getting a syntax error with my Shell arithmetic?
I have a problem with a linux shell script (sh).
I'm trying to write a script that calculates combinations, but I think I get overflows when
trying to calculate faculties. So, I'm trying another ...
- 151
2
votes
0
answers
376
views
How can I check which shell I am currently using? [duplicate]
Possible Duplicate:
How to test what shell I am using in a terminal?
An echo $SHELL will only display the value of the SHELL variable which would indicate the default shell on the system.
But I ...
- 34.7k
5
votes
3
answers
6k
views
Make terminal text color different when in ssh session
Is there a way to make my terminal (konsole) display different text colors when I'm in an ssh session WITHOUT modifying the remote host's color configuration? Like, maybe automatically switching to a ...
- 12.9k
29
votes
4
answers
32k
views
touch: cannot touch `foo': No such file or directory
What could cause touch to fail with this error message?
touch: cannot touch `foo': No such file or directory
Note that an error due to incorrect permissions looks different:
touch: cannot touch `...
- 8,167
55
votes
1
answer
28k
views
Difference between shell variables which are exported and those which are not in bash
Bash seems to differentiate between variables which have been exported and those which have not.
example:
$ FOO=BAR
$ env | grep FOO
$ set | grep FOO
FOO=BAR
set sees the variable but env does not.
...
- 27.2k
6
votes
2
answers
990
views
How can I display the time when a command was executed in my bash prompt?
Currently my bash prompt looks like this
$ echo $PS1
# \[\e[34m\][\t]\[\e[0m\] \[\e]0;\w\a\]\[\e[34m\]\u@\h: \[\e[34m\]\w\[\e[0m\]\n$
$
The problem is that \t will only display the time when the ...
- 34.7k
6
votes
4
answers
379
views
How could I simplify this command to only use awk?
awk '/user/ {print $1 }' /etc/userdomains | sed 's/://'
the format of /etc/userdomains is
domain.tld: user
otherdomain.tld: otheruser
- 58.5k
10
votes
3
answers
7k
views
How do I take a list and remove it from a file?
I have a long list of domain names that I need to remove from /etc/remotedomains. They're probably not in any particular order in the file. Each domain is on one line.
How could I iterate through the ...
- 58.5k
123
votes
8
answers
230k
views
Grabbing the first [x] characters for a string from a pipe
If I have really long output from a command (single line) but I know I only want the first [x] (let's say 8) characters of the output, what's the easiest way to get that? There aren't any delimiters.
- 58.5k
6
votes
2
answers
2k
views
How to make sure that I use the latest version of bash?
I just setup bash v4.1.0 on my machine.
The old version is under /bin/bash. Is there a way to use the newer version of bash without replacing the old one from /bin? I want the newer version to be ...
- 34.7k
9
votes
2
answers
6k
views
What are the new features available to bash 4?
I was using bash3 up to now, and just got a copy of the latest version
$ ./bash --version
GNU bash, version 4.1.0(1)-release (i686-pc-linux-gnu)
Copyright (C) 2009 Free Software Foundation, Inc.
...
- 34.7k
25
votes
4
answers
14k
views
Share aliases and PATH setting between zsh and bash
The shell that I normally use is zsh. I have several aliases to enable color in some programs such as ls and grep. I've also set my custom path so that I can execute programs in non-standard place (...
- 20.1k
5
votes
3
answers
205
views
How do I remove every file that has x in its title?
I have a lot of directory where there are hundreds of files.
In every directory there are pairs of my_file-01.jpg and my_file-€01.jpg
I want to remove every file that contains € sign in its title: ...
- 241
57
votes
5
answers
20k
views
What are the fundamental differences between the mainstream *NIX shells? [closed]
What are the fundamental differences between the mainstream *NIX shells and what scenarios might prompt you to use one over the other? I understand that some of it probably comes down to user ...
- 1,523
18
votes
4
answers
44k
views
Remove end of line characters from stdout? Multiple lines into a single line
I have a script which outputs the following text. This is the output from a Netopia 2210-02 ADSL2 modem.
ADSL Line State: Up
ADSL Startup Attempts: 1
ADSL Modulation: DMT
ADSL Data ...
- 19.5k
88
votes
3
answers
38k
views
What is the bash shortcut to change to the previous directory?
Sadly, I only learned about this last year by stumbling upon it randomly on the internet. I use it so infrequently that I always forget what it is by the time I need it again.
How do you change to ...
- 1,183
5
votes
3
answers
3k
views
renaming files without the **rename** command
I have a directory of files,
Measurements Panama 2009-03-22 Session1.xml
Measurements Panama 2009-03-22 Session2.xml
Measurements Panama 2009-03-22 Session3.xml
Measurements Panama 2009-03-22 ...
- 5,311
8
votes
6
answers
4k
views
How can I reproduce commands run on one machine on another machine?
I would like to install some software on a linux-machine that I have run in VirtualBox. Then I would like to do the same thing on a linux-VPS.
I think that I can save all commands that I run using ...
- 1,593
78
votes
8
answers
131k
views
grep and tail -f?
Is it possible to do a tail -f (or similar) on a file, and grep it at the same time? I wouldn't mind other commands just looking for that kind of behavior.
- 58.5k
40
votes
5
answers
14k
views
How to know the "level" of shells I am in?
If I open a terminal like xterm I will have a shell. Then if I use ssh or zsh I will have another "level" of shell. Is there a way to know how many times I have to Ctrl+D or type exit to exit all of ...
- 20.1k
5
votes
2
answers
1k
views
RS232 chat. Simplest way?
I'm working in a project in which I will have to deal with serial communications. For testing, I want make to 2 computers speak to each other (with my interaction) via RS232.
Will the next thing work?...
- 1,024
1
vote
1
answer
2k
views
error using "du" command
I am on the university machine trying to estimate the disk usage I have on my space I do
du -csh ./
from the begining of my account, but an error is given that ./Yesterday/Yesterday is not a device, ...
- 5,311
6
votes
1
answer
9k
views
Read space as input in shell script [duplicate]
How can I give space " " as input in shell script ?
Ex :
echo " Enter date for grep... Ex: Oct 6 [***Double space is important for single date***] (or) Oct 12 "
read mdate
echo $mdate
I get the ...
- 893
40
votes
5
answers
26k
views
Save complete GNU screen session state
Is it possible to persist the "state" of a GNU screen window (or just a standard shell) so that I can reload everything after a reboot:
The number of opened shells
The name of each shell
The current ...
- 5,155
286
votes
12
answers
438k
views
How do I convert an epoch timestamp to a human readable format on the cli?
How do I convert an epoch timestamp to a human readable format on the cli? I think there's a way to do it with date but the syntax eludes me (other ways welcome).
- 58.5k
6
votes
3
answers
800
views
Correct textual name for <<
I've just come across the << command, used like so:
cat > outfile.txt <<EOF
Multi-line content
that will be written to outfile.txt
EOF
Now, I've no idea what this is called, but I'd ...
- 1,141
17
votes
7
answers
6k
views
Is it bad practice to set root's shell to something other than the default?
Once a friend of mine (who is an experienced Unix/Linux user) told me that setting root's shell to something other than sh (i.e bash or zsh) might create problems, because some script might assume ...
- 20.1k
20
votes
5
answers
29k
views
how to pass the result of `find` as a list of files?
The situation is, I have an MP3 player mpg321 that accepts a list of files as argument. I keep my music in a directory named "music", in which there are a few more directories. I just want to play all ...
- 20.1k
10
votes
1
answer
13k
views
how to view a directory's permission
What is the command with which you can directly view the permission bits of a directory?
- 307
4
votes
3
answers
1k
views
`$XAUTHORITY` appears from 'nowhere' on su+tmux
When I switched from su+bash to su+tmux+zsh I noticed that I get the $XAUTHORITY variable defined as /root/.xauthXXXXXX where XXXXXX are 6 random alphanumeric characters. With the previous ...
- 16.6k
1
vote
1
answer
826
views
how to convert ^I character
I have a text file like this:
info Some info here
In which when I use cat -A display this:
info^I Some info here
How do I edit this so I'll get something like this instead:
info<space>-<...
- 343
1
vote
2
answers
605
views
Problematic build script with quotes
Hi I'm trying to create a build script that executes these commands:
cd libiconv
../../src/libiconv/configure --prefix=/home/ruben/mingw64/build/gcc-libs \
--host=x86_64-...
- 370
0
votes
0
answers
351
views
bash: recall command by typing some characters of it [duplicate]
Possible Duplicate:
best way to search my shell's history
In MSDOS I have the option to start typing some characters of a previous command and then pressing F8 it will search the command ...
Jose M Balaguer
3
votes
2
answers
2k
views
Extending history search in zsh
How to extend Ctrl+R search in zsh? It cannot find entry despite it is in history file.
Edit: My .zshrc:
setopt AUTO_CD
setopt CORRECT_ALL
setopt EXTENDED_GLOB
# History
SAVEHIST=10000
HISTFILE=~/....
- 16.6k
25
votes
11
answers
25k
views
Tool in UNIX to subtract dates
Is there any tool in Solaris UNIX (so no GNU tool available) to subtract dates? I know that in Linux we have gawk that can subtract one date from another. But in Solaris the maximum we have is nawk (...
- 657
7
votes
2
answers
3k
views
dash compatibility to bash
Wikipedia says that dash executes faster than bash. My question is, if I set /bin/sh to dash, will all scripts that use /bin/sh in their shebang line that was intended for bash work under dash?
- 3,840
6
votes
2
answers
913
views
modify path globally
Is there a standard for $PATH and the order of things that are supposed to be in there? out of the box Arch Linux doesn't have /usr/local/bin in the $PATH. I want to add it but I'm not sure if there's ...
- 58.5k
49
votes
10
answers
83k
views
Grabbing the extension in a file name
How do I get the file extension from bash? Here's what I tried:
filename=`basename $filepath`
fileext=${filename##*.}
By doing that I can get extension of bz2 from the path /dir/subdir/file.bz2, but ...
- 3,840
8
votes
1
answer
1k
views
Whenever I type some wrong command, my terminal tries to run that command in the background
Something strange started happening to my terminal. Whenever I type some wrong command it tries to run that command in the background.
hegeek@colinux: ~# l
[9]+ Stopped l
thegeek@colinux: ~# ...
- 6,872
3
votes
1
answer
1k
views
Emacs mode in zsh: M-b M-f etc. show weird symbols
I have set up zsh to use emacs mode. But typing Alt+f or Alt+b inserts weird symbols (accented letters and so on), rather than moving around by word in the shell like it should. Since I don't ever ...
- 3,573
2
votes
3
answers
418
views
Directory filenames with sed with whitespaces
I'm working on a script and I'm stuck, even with the help of the google.
Here's my code:
for FOLDER in `find . -type d | sed "s#^.#$(pwd)#" | sed 's/ /\ /g'`
do
echo "$FOLDER"
done
This will ...
- 363
23
votes
10
answers
44k
views
How do I change folder timestamps recursively to the newest file?
I was wondering if anyone knows how to change the timestamps of folders recursively based on the latest timestamp found of the files in that folder.
So for example:
jon@UbuntuPanther:/media/media/...
- 363
486
votes
10
answers
207k
views
How do I delete a file whose name begins with "-" (hyphen a.k.a. dash or minus)?
How do you remove a file whose filename begins with a dash (hyphen or minus) -? I'm ssh'd into a remote OSX server and I have this file in my directory:
tohru:~ $ ls -l
total 8
-rw-r--r-- 1 me ...
- 4,963
4
votes
3
answers
3k
views
Understanding sudoers:
I have a Unix script which creates a temporary log file, say tempfl.log.
When this file is created it has permission rw-r--r--.
There is a line
chmod 0440 /etc/sudoers tempfl.log 2>&1
But ...
- 153