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, …).
1
vote
1answer
25 views
Run Comand on all files (folders ad subfolders) [duplicate]
All, I have a lot of PDF files. Does there exist a way to apply to all PDFs in folder and sub-folders at one time?
Example, I have:
/pdf/test/pdfa.pdf
/pdf/example/aa/test.pdf
I'd like to apply ...
3
votes
1answer
33 views
Problem combining -or and -exec with find command
I'm finding that when I use find's -or operator in combination with -exec, I don't get the result I expect. When searching for .cpp and .h files, the command works as expected if I don't use -exec:
...
9
votes
1answer
167 views
Why does `postgres` require a shell?
In my Debian Wheezy systems, I noticed that the postgres user 'postgres', the "PostgreSQL administrator", uses /bin/bash as shell.
However, I cannot figure out why this is needed. Changing this to ...
0
votes
1answer
20 views
I ran `zsh -v` and now I have no shell history [on hold]
I just installed zsh today to try it out. I was trying to check my zsh version and I accidentally entered zsh -v which is the verbose option.
Now I can't seem to use reverse search on history. How ...
0
votes
0answers
19 views
Redirect a directory as input to a script and output to a file
I want to use a directory name as a parameter for a pre-made script. Then the output goes into a newly made file in the home directory. It involves pipe/redirection. How do I do that?
read dir
$dir ...
0
votes
0answers
54 views
Which component does depend on “importing shell functions from environment variables” feature? [on hold]
This is my first question. Which component does rely on the bash feature "importing functions from environment variables"? (Let me call it "BASH_FUNC import" feature here). I want to know "actual ...
7
votes
2answers
135 views
Why is a variable visible in a subshell?
The Learning Bash Book mentions that a subshell will inherit only environment variables and file descriptors, etc., and that it will not inherit variables that are not exported:
$ var=15
$ (echo ...
3
votes
2answers
85 views
leaking memory with shell script and tty [on hold]
I'm running a shell script on a raspberry pi to communicate with a arduino.
Every hour my ram gets used up by about 50 megabytes more.
The script itself just connects to ttyACM0 (the arduino's usb ...
5
votes
4answers
197 views
Is there a difference between read, head -1, and sed 1q?
The following commands seem to be roughly equivalent:
read varname
varname=$(head -1)
varname=$(sed 1q)
One difference is that read is a shell builtin while head and sed aren't.
Besides that, is ...
14
votes
4answers
870 views
Do we have more history for cd?
cd - can move to the last visited directory. Can we visit more history other than the last one?
2
votes
4answers
41 views
Bash - How do I loop through subdirectories and extract the files
I have a directory called 10K_TIF (main directory). Within this main directory are multiple sub-directories each containing tif images. I want to read each TIF image and extract its path using a bash ...
4
votes
2answers
55 views
How to capture ordered STDOUT/STDERR and add timestamp/prefixes?
I have explored almost all available similar questions, to no avail.
Let me describe the problem in detail:
I run some unattended scripts and these can produce standard output and standard error ...
0
votes
1answer
14 views
Asking how to packing multiple files (tar) with shell script [on hold]
I'm new to shell scripting and I have some tar files like this:
AOC-1*.tar
SAA-2*.tar
BCX-4*.tar
TXP-5*.tar
and I have a shell script like this:
#!/bin/sh
last=`ls [SAA]*.tar | sed s/.tar//g | ...
2
votes
2answers
29 views
Interacting with a running interactive console program from a different process
I have a console program with an interactive shell, similar to say, the Python interactive shell. Is there an easy way to start this interactive program A and then use another program B to run A? I ...
1
vote
1answer
43 views
/bin/sh: error importing function definition for `some-function'
I encountered this error when updating bash for the CVE-2014-6271 security issue:
# yum update bash
Running transaction (shutdown inhibited)
Updating : bash-4.2.47-4.fc20.x86_64
/bin/sh: error ...
1
vote
1answer
46 views
Is it possible to create a Linux environment without a traditional command shell?
i.e.
Using something like IPython, re.pl, or somesuch as a login shell, instead of bash/ksh/etc.
Using initscripts, etc. written in Python or some other scripting language, and making no use of ...
0
votes
1answer
26 views
How to move cron commands into a script?
Can someone give me an example that shows how to put Cron commands into a script? Using these commands as an example:
find /home/network/public_1 -type f -ctime -1 -exec ls -ls {} \;
find ...
3
votes
1answer
36 views
Make program in a pipe to think it has tty
Test environment:
$ mkdir testdir
$ cd testdir
$ echo | tee "file
name"
Now, ls will print file?name (under Ubuntu GNU bash, at least), while ls | cat will print file and name in separate lines.
...
0
votes
2answers
18 views
Rsync'ing system, exclude doesn't seem to work
I'm trying to make a full filesystem backup of a server through rsync, following this guide.
I'm using the following command:
rsync -aAXH --progress --delete --stats --exclude={\
"/dev/*",\
...
0
votes
4answers
37 views
How to get process id of a command
We are running some command in batch mode. We need to do some more tasks once the existing command is done, so we need to wait until this command is done.
For example:
bsub -q gui -I calibre -drc ...
1
vote
1answer
60 views
How does Git change the shell prompt in Aptana Studio's Cygwin Terminal?
I'm running Aptana studio 3.3.2. The command echo $SHELL outputs /bin/sh.
However there is no value for the PS1 environment variable which I would
like to inspect. I cannot there is no .bash_profile ...
1
vote
1answer
24 views
Interactive Shell Session from Java
I want to run a series of commands from Java. I came across few forums that explain how to execute multiple commands using getRuntime().exec(command) and defining command as String[]. But I want to ...
0
votes
1answer
61 views
Copying files with multiple extensions
I would like to copy files with multiple extensions to a single destination directory.
For example, I can use the following command to copy all .txt files in the working directory to a directory ...
2
votes
2answers
431 views
Assign Subshell background process pid to variable
I am currently starting a background process within a subshell and was wondering how can I assign its pid number to a variable outside the subshell scope?
I have tried many different ways but MYPID ...
1
vote
1answer
22 views
Icon stops loading after the application restarts
I have a application which uses "self-restart" mechanism. It kills itself and runs again. When I run it first time (with .desktop file) it loads its icon correctly. The problem is that when it ...
1
vote
3answers
53 views
How to get the pid of a process and invoke kill -9 on it in the shell script? [duplicate]
I have an application server which we start by running this below command and as soon as we run the below commnad, it will start my application server
/opt/data/bin/test_start_stop.sh start
And to ...
1
vote
1answer
34 views
du skip symbolic links
I cannot find an example of what I want to do and, from what I'm reading, the default behavior of du on my system is not the proper default behavior.
If I ls my /data folder, I see (removing the ...
-2
votes
0answers
14 views
UNIX .vimrc settings not preserved after running Screen command
After the terminal window first appears, I run Screen to split the screen horizontally. I notice however that my settings for VIM in .vimrc are not "preserved". Is there a way to fix this? I am ...
1
vote
1answer
74 views
Why are UNIX shells like this and how can I work around it?
One of the things I've noticed about BASH and other UNIX shells is that, by default and when used in typical ways, they spawn subshells for almost everything.
e.g.
foo=$(grep "someword" ...
0
votes
1answer
41 views
Changing my default directory in passwd changes my prompt
I don't understand what's happening in this scenario.
I changed the home directory of a user by editing the /etc/passwd file instead of using usermod -d. It worked: the default directory wasn't ...
0
votes
3answers
31 views
Shell pattern matching vs. regular expressions occurence [duplicate]
I am relatively new to Unix, and I stumbled across one curiosity. Some shell constructs like case or find, employ pattern matching, but it is not quite regex. Other commands, like ed, sed, vi, and ...
2
votes
2answers
38 views
List of subdirectories that contains a particular file name
I am wondering if i can do this in a single shell command.
I am in home directory and want to find a list of subdirectories that contains a particular file. The file name and the depth is always ...
0
votes
1answer
34 views
How do I switch from bash to zsh? [duplicate]
I can start zsh with zsh.
How can I make it be the default for new terminal windows?
Will it be ok to copy my .bashrc to .zshrc to get things like my customized PS1 prompt.
-2
votes
6answers
65 views
How to change to normal user in the command line when logged in as the root user?
I log into an system through root via ssh.
How do I become the normal user or another user on the system?
1
vote
3answers
83 views
How to find md5sum of files on remote machines by doing ssh?
I am running my below shell script on machineC which gets the md5sum of my files in my PRIMARY directory in machineC itself.
#!/bin/bash
export PRIMARY=/data01/primary
for entry in "$PRIMARY"/*
do
...
0
votes
1answer
30 views
Permission denied while getting the md5sum of a file using shell script?
I am running my below shell script which gets the md5sum of a files in my PRIMARY directory
#!/bin/bash
export PRIMARY=/data01/primary
for entry in "$PRIMARY"/*
do
local_md5sum=/usr/bin/md5sum ...
2
votes
1answer
43 views
Bash - how to make explicit operator precedence without creating a subshell
I'm sure this is posted somewhere, but I haven't been able to find it.
In Bash, how does one specify operator precedence (aka command grouping) without creating a subshell? In most other languages ...
3
votes
1answer
25 views
More shell scripts than one in one text file?
I am learning shell scripting for my introductory UNIX course at my university, and I`m curious if is it possible to have more than one shell script in one text file. What I mean by that is, for ...
0
votes
2answers
27 views
Add space after 8 characters then add space after every 4 characters
Here is the sample input:
AbbigailAbieAbbyAbbi
Using sed, I have separated them into 4 characters but seems like I got a problem because I have to separate the first 8 characters first then add ...
0
votes
1answer
43 views
How to invoke shell function in string? (bash)
I want to invoke shell function in string. Here is my use case:
function envfoo() {
env ENV_FOO=foo $@
}
function envbar() {
env ENV_BAR=bar $@
}
$ envfoo env |egrep ENV_
ENV_FOO=foo
$ ...
1
vote
1answer
11 views
Increase character width in Ubuntu server shell?
Is there any way to increase the character width from 80 to something higher in the shell in an Ubuntu server?
1
vote
2answers
149 views
I accidentally GZIPed a whole bunch of files, one by one, instead of using tar(1). How can I undo this mess?
I'm new to the gzip command, so I googled some commands to run so I can gzip an entire directory recursively. Now while it did that, it converted each of my files to the gzip format and added .gz to ...
8
votes
4answers
442 views
How do I remove spaces from shell variables?
I have done the following at command line:
$ text="name with space"
$ echo $text
name with space
I am trying to use tr -d ' ' to remove the spaces and have a result of:
namewithspace
I've tried ...
5
votes
3answers
127 views
I am trying to find a better/easier way to count alphabetic characters in a file or shell variable
I have a file containing the following text:
we are going to write something 1 2 3
wc tells me I have 1 line 9 words and 38 characters.
I'm looking to count the 26 letters only (a-z, no numbers or ...
5
votes
3answers
104 views
Bash script error with strings with paths that have spaces and wildcards
I am having trouble getting the basics of Bash scripting down. Here's what I have so far:
#!/bin/bash
FILES="/home/john/my directory/*.txt"
for f in "${FILES}"
do
echo "${f}"
done
All I want to ...
0
votes
3answers
130 views
bash find using variable
I have an issue I don't understand. It is simple and it should work, but it doesn't.
=EDITED exactly what I can see from terminal=
I have a list of filenames:
[molni@archlinux picasa_album]$ cat LIST
...
2
votes
1answer
39 views
how to execute a shell built-in if find found certain files
In general, if we want to execute a command if find identifies files corresponding to certain specs, we can use -exec. But in my case I want to exit the shell/script if find found a match and -exec ...
1
vote
2answers
42 views
Pass arguments to a command run by another user
I have a bash script that is supposed to take some arguments and then run in a different user: test.sh
#!/bin/bash
sudo su user2 <<'EOF'
echo $1
EOF
However it prints blank:
$ ./test.sh ...
0
votes
2answers
11 views
How can I sudo su and change directory just after?
I would like to create an alias that does something like this:
alias userYYY='sudo su userYYY; cd /a/path/that/only/userYYY/has/access'
So then from my command line, I am logged in with a sudoer ...
0
votes
0answers
29 views
How to get diff for HTML reports?
echo "New defects"
echo "==============================="
n=0
def_num=0
while read line; do
n=$((++n))
if echo $line | grep '^[[:space:]]*>' &>/dev/null; then
if [ $(($n % ...
