Questions about bash only, as opposed to other Bourne/POSIX shells. For all Bourne/POSIX-style shells, use the /shell tag instead.
0
votes
0answers
31 views
Error while compiling bash for shellshock security exploit
I used the instruction from https://shellshocker.net/
here is the command:
sudo curl https://shellshocker.net/fixbash | sh
error while compiling:
Running make
rm -f mksyntax
gcc ...
9
votes
1answer
58 views
Disable tab completion in Bash for some directory that contains a large number of files?
I'm working with large number of files, which I keep in a directory. Every time I go in to that directory and accidentally press Tab twice, it takes too long (may be over a minutes) to show files that ...
0
votes
3answers
50 views
Can dash replace bash as my default shell?
From what I read, dash can be made as a shell by using the command
~$ chsh shirish
Password:
Changing the login shell for shirish
Enter the new value, or press ENTER for the default
Login Shell ...
5
votes
2answers
639 views
Why doesn't 'sudo bash && cd desktop' cd in to the desktop folder? [duplicate]
I have a folder with chmod 000 permissions on it with a lot of different stuff in, the way I get in is a start bash in sudo by running sudo bash.
Why can't I do &&? I want to cd into the ...
0
votes
0answers
17 views
history - bash, dash, zsh and .profile [duplicate]
For a long time I have been wondering about the existence of many shells in GNU/Linux. To make the question a bit focused I have used only three shells - bash, dash and zsh.
From wikipedia articles ...
1
vote
1answer
15 views
Partially duplicated history when setting PS1 in .bash_profile [duplicate]
When I set PS1 variable in ~/.bash_profile, it worked as configured. However, the history is somehow messed up.
When I press Arrow Up or Ctrl+P to view commands I typed, it starts to duplicate ...
0
votes
1answer
17 views
Applying patch for bash failing
The bash shell in my production box is vulnerable to 'bashbug' vulnerability. https://securityblog.redhat.com/2014/09/24/bash-specially-crafted-environment-variables-code-injection-attack/
The ...
0
votes
1answer
21 views
What is the difference between the built in echo command and /bin/echo? [duplicate]
I was playing around with the type and which commands and I discovered something strange.
type either returns the path or says that a command is a Bash built in.
which either returns the path or ...
-1
votes
1answer
34 views
How to remove only 0-9 character long numbers from a file?
How can we remove only the numbers that are 0,1,2,3,4,5,6,7,8,9 character long from a file? I mean the lines that are matching this pattern.
Example for removable lines:
cat input.txt
1
123423113
...
0
votes
2answers
40 views
Bash Script using read needs to stop executing on Ctrl+D
I need to write a script that will add a line to a text file if Enter is pressed.
But, if Ctrl+D is pressed, I need to exit that loop in the bash.
touch texttest.txt
LINE="0"
while true; do
read ...
1
vote
2answers
49 views
How to do a grep on remote machine and print out the line which contains those words?
I have few logs files in my machineB under this directory /opt/ptd/Logs/ as shown below - My logs files are pretty big.
david@machineB:/opt/ptd/Logs$ ls -lt
-rw-r--r-- 1 david david 49651720 Oct 11 ...
5
votes
1answer
33 views
Representing/quoting NUL on the command line
Can \0 be used on the command line?
Background
For testing corner cases in GNU Parallel I was curious whether all characters were correctly quoted on the command line. Most of them are:
perl -e ...
0
votes
0answers
40 views
BASH-3 update: how to revert / undo the changes?
I am using Mint 17, 64-bit with Cinnamon.
I recently updated Bash and following the update mint drivers are missing and mint is not working. So I want revert the changes. How can I do it?
For ...
1
vote
2answers
72 views
Motion start sequence - shell script modification
I've tried to modify this script to start Motion using the following libraries.
I start the script by entering the following command into terminal:
sudo /etc/init.d/motion start
Which Gives:
...
0
votes
1answer
57 views
What are the types of ~, ~-, ~+, *?
If I am correct, pwd is a command, PWD is a variable('s name), and - in cd - is an operand.
What are the types of ~, ~-, ~+, * when they mean $HOME, the previous visited dir, the current dir, and the ...
0
votes
0answers
29 views
What does && mean in cd “$OLDPWD” && pwd? [duplicate]
What does && mean in cd "$OLDPWD" && pwd?
Is it used to connect two commands and run them sequentially in some way?
Is it a logical operator of bash?
0
votes
1answer
56 views
shell script edited on windows displays unexpected error message [duplicate]
I am having some trouble running a script to ssh to a remote server. If I simply ssh from the command line I have no trouble reaching the server, but when I run a script to do this I get an error, ...
3
votes
2answers
226 views
How does exec bash builtin work internally?
From this link I get the following about exec bash builtin command:
If command is supplied, it replaces the shell without creating a
new process.
How does it exactly replace the shell (i.e. ...
3
votes
1answer
70 views
How can I create an alias that passes additional arguments?
I have an executable that I use often:
/dir1/dir2/dir3/dir4/executable argv[1] argv[2] argv[3]
I know that I can set an alias for the executable:
alias myexecutable = ...
-2
votes
1answer
72 views
How can I update BASH [duplicate]
How can I update BASH?
I noticed that there are version 4.2.45
env x='() { :;}; echo vulnerable' bash -c "echo this is a test"
this is a test
cat /etc/redhat-release
CentOS release 5.11 (Final)
rpm ...
0
votes
3answers
16 views
Redirect stderr and stdout to another file descriptor
exec 6>&1 will copy file descriptor 1 onto 6.
But how can I copy both stderr and stdout (1 and 2)to file descriptor 6 ?
3
votes
3answers
303 views
Better way to run single for loop instead of two for loops
This works but the way I did this is kind of silly. Is there a better way to do this?
for e in $(ipcs | awk '{print $2}'); do
[[ "$e" = "Semaphore" ]] && break
echo $e
ipcrm shm ...
4
votes
3answers
228 views
How do I auto complete a command from the command history? [duplicate]
Is there a key combination for bash to auto compete a command from the history? In ipython and matlab for example this is achieved by pressing up arrow after typing a few characters.
3
votes
1answer
98 views
How can I run a bash variable as a command exactly without additional quotation?
I'm trying to make a script which needs to save a command to be run as a string. The string in question needs to contain quotes, and when attempting to execute it bash adds additional quotation ...
-1
votes
1answer
37 views
syntax error: unexpected end of the file
#!/bin/bash
#organization: Seneca College
#Purpose: Validate a date
#Usage: chkdate year month day
#
year=$1; month=$2; day=$3; extra=$4
if [[ "$year" == "" || "$month" == "" || "$day" == "" ]]; then
...
-1
votes
1answer
32 views
how to select multiple exit
I'm new to bash scripting and I don't understand what's wrong with this specific part of my script. im trying to select all the exit that have in my script. and trying to put in conditon that if all ...
2
votes
3answers
114 views
Can you source a “here document”?
Let's say I have a bash script that acts as a config file for another bash script:
config.sh:
verbose=yes
echo "Malicious code!"
name=test
script.sh:
source config.sh
echo "After sourcing: ...
1
vote
1answer
93 views
Shellshock - not vulnerable with bash version 4.1?
We have several Amazon servers. It has bash version 4.1.2. Kaspersky claims that all bash versions up to 4.3 are unsafe. When I do this test...
env x='() { :;}; echo vulnerable' bash -c 'echo hello'
...
2
votes
2answers
73 views
Bash not equal string comparison
Why does this cause an infinite loop?
#!/bin/bash
while [[ "$(ipcs | awk '{print $2}')" != "Semaphore" ]]; do
#Gonna get rid of the echo after working
echo "$(ipcs | awk '{print $2}')"
#I wanna ...
2
votes
0answers
36 views
Why do some processes pass on their cpu usage to another process when it ends?
I have wondered this for a while.
For example, lets say process1 is a process that uses a lot of cpu power, like 90%. Its a video game. Then i have process2 which uses 10-12% cpu. Its a web browser.
...
1
vote
1answer
59 views
Why is variable assignment preceding command ignored? [duplicate]
The bash 4.1 manpage states (emphasis added)...
Simple Commands
A simple command is a sequence of optional variable assignments
followed by blank-separated words and redirections, and ...
0
votes
1answer
74 views
Bash if statement [: missing `]' error [duplicate]
I am having trouble with bash. I am trying to put a command in an if statement and then compare it to a string.
This works perfectly.
echo $(ipcs | grep Shared | awk '{print $2}')
When I put it in ...
2
votes
1answer
62 views
Copy multiple files and create the target directories at the same time?
I read How can I copy a file and create the target directories at the same time?
But the solution there only works if you want to copy one file.
How would I copy multiple files into a directory, ...
1
vote
3answers
106 views
bash script that reads user input and uses “cal” command to validate dates
I want to write a script that reads my input (for example if my script is called "check", then I would type "check 9 4 1993" and that input would go through the cal command and will check through the ...
2
votes
0answers
39 views
bash syntax error near unexpected token `(' - but everything looks like it should work [duplicate]
I'm trying to write a bash script which will copy a bunch of files and directories from a directory, omitting a couple but taking everything else.
I have got a command that does this and works from ...
5
votes
2answers
576 views
How do I delete all of a set of files in a random order?
I have a set of files, all that are named with the convention file_[number]_[abcd].bin (where [number] is a number in the range 0-size of drive in MB). i.e there is file_0_a.bin, file_0_b.bin, ...
0
votes
1answer
16 views
Shell script permission denied despite +x flag
This is an odd one, it only happens on one server (shared hosting, so I have limited access to configuration and logs), but I can't wrap my head around it.
I have a shell script which runs some app's ...
4
votes
3answers
304 views
How to check whether a process is daemon or not?
I have written a small daemon that starts at the boot time and does all the things perfectly like writing in the log file. But I want to know, how can we check whether that process is daemon or not? ...
1
vote
2answers
80 views
bash question about if and then
I'm writing this in my script. It has other parts but I'm getting stuck on this part only.
if [[$# == $year $month $day ]] ; then
cal $day $month $year
fi
When I run this it give me this msg:
...
0
votes
1answer
50 views
how to write this if command?
my script name is 1. when i type in "1 2012 12 12". it shows current date calendar and when i enter a invaild date like "1 2323232" cal gives me a error so how could i put that in if loop that if it ...
5
votes
2answers
359 views
Did the shellshock bash fix break basic command line tools like echo and cat? [duplicate]
I used to be able to do things like:
X=123 cat <<EOF
X is $X
EOF
or even simpler:
X=123 echo $X
The first one still seems to work on Mac OS X after install the bash fix, however neither ...
-1
votes
1answer
27 views
how to create a dynamic password thats between 8 and 16 characters [duplicate]
This is my password generator and it generates 8 characters and shuffles them. But i need to make it dynamic length. How would i go about doing that. So the output would be different length between 8 ...
0
votes
0answers
26 views
use EOF in a one-liner?
I have a simple script that executes commands on remote host using ssh and EOF
I was trying to do it with a one-liner at command line but I couldn't figure out how to do the EOF outside of a script. ...
1
vote
0answers
39 views
export -f in .bashrc after upgrade to bash 4.3.30 kills builtins?
I recently upgraded my bash (Mac OS X 10.6.8) from 3.2.48(1) to 4.3.30(1) via macports, and while the install seems to have gone smoothly, the two spots in my ~/.bashrc where I had export -f myfunc; ...
0
votes
0answers
47 views
Can call login command from terminal
I want to create a user using useradd from root in my terminal window, after it I call passwd to set user's password.
So I cant call login username because when I call it from terminal it closes ...
0
votes
1answer
27 views
generate password that is random length between 8 - 16 ( i have the generator but its not dynamic) [duplicate]
This is my password generator and it generates 8 characters and shuffles them. But i need to make it dynamic length. How would i go about doing that. So the output would be different length between 8 ...
2
votes
4answers
186 views
Creating symbolic link recursively
I essentially want to run this command...
ln -s /opt/gitlab/embedded/service/gitlab-shell/hooks/ /var/opt/gitlab/git-data/repositories/web/*/hooks
This would create a symbolic link in all folders ...
2
votes
3answers
62 views
How to nest quotes in bash commands
I want to test the result of this command:
dmesg | grep "Firmware patch 1563"
Therefore, I try to write something like this:
if [ "`dmesg | grep "Firmware patch 1563`" == "" ]
But it doesn't ...
1
vote
1answer
56 views
Replace pattern in file with pattern in second file
I want to replace part of a file's data, with data from another file.
Suppose file1 has data as is written below and file2 has some data I want to store and replace file1 data from file2 from ...
0
votes
0answers
30 views
patch bash at sunos5.7
Refer:shellshock solution for nexenta/solaris post for shellshock solution
may I confirm the command is method1:
/usr/local/bin/curl \
https://ftp.gnu.org/pub/gnu/bash/bash-3.2-patchs/bash32-001 ...
