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, …).

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6
votes
5answers
191 views

How to execute a bash command in all possible subdirectories?

Let's say my main directory is /home/test Under it i have lots of subdirectories and under subdirectories still a lots of them and so on. Example: /home/test /home/test/subdir1 ...
2
votes
4answers
1k views

Find directories that do not contain subdirectories

I'm writing script is ksh. Need to find all directory names directly under the current directory which contain only files, not subdirectories. I know that I could use ls -alR and recursively parse ...
1
vote
1answer
46 views

A question about shell and .profile,.bash_profile,.bashrc

I'm on aix 7.1,my shell is bash if i did ssh ibmunix gqlplus user/pass All works and gqlplus start,gqlplus is on /opt/freeware/bin If i did from another machine ssh ibmunix "gqlplus ...
7
votes
1answer
130 views

Why there isn't a new line at the end of quoting a subshell and passing the results to echo?

When I do ls | grep png the output of grep is: 2015-05-15-200203_1920x1080_scrot.png 2015-05-16-025536_1920x1080_scrot.png (filename,newline,filename,newline) then, echo $(ls | grep png) outputs: ...
0
votes
3answers
38 views

How can I add a line including single quotes to a file with sed [duplicate]

I want to append the following line to a text file with sed: gem 'forum2discourse' I've tried sed -i '$a gem \'forum2discourse\'' Gemfile but this drops me to a > prompt so I think I must be ...
0
votes
0answers
40 views

How to rewrite the comand using I/O redirections?

Is there any way to rewrite the following command using only I/O redirections and not pipes ? ls -l | grep User | wc -l | tail -l
8
votes
3answers
12k views

How to discover a new line using a for loop?

In various places around the web I've found: \015 \012 \x0a - hex \n \r all as synonyms for various newlines / carriage returns... But in this small script I cannot recognise when I come across a ...
14
votes
1answer
565 views

What's the magic that allows me to tab-complete remote files as I type an scp command?

Presumably this is a feature provided by some plugin I have enabled in my oh-my-zsh setup (I have been using zsh for many years now). I noticed ever since I added my public key to the server (now I ...
1
vote
2answers
59 views

How to perform grep on 'man unix_command'?

Often while going through the output of man man awk I Need to perform grep, for e.g. in man awk, I need to find the definition of a particular flag, variable etc. Can anyone tell me, what would be ...
1
vote
1answer
44 views

Searching a filename

How to search a file with a given String and currentTimestamp and if not found trigger a mail? For Ex-:I have to search a file whose filename would be like filename_05172015 and trigger a mail if not ...
2
votes
1answer
358 views

How to implement retry mechanism while executing the server url in the shell script?

I am working on a project in which I need to make a url call to one of my server from the bash shell script.. http://hostname.domain.com:8080/beat After hitting the above url, I will be getting the ...
9
votes
3answers
2k views

find with -execdir

I run a find with -execdir both I don't get the results I was expecting. SSCCE below: mkdir -p a/b/c find . -type d -execdir touch foo \; $ tree a a ├── b │   ├── c │   └── foo └── foo Directory c ...
-2
votes
0answers
45 views

Convert perl to shell/bash [closed]

I understand C and C++ and new to perl scripting. I must convert the perl script under the following url to shell or bash: busware Here is the code: #!/usr/bin/perl use warnings; use strict; use ...
21
votes
1answer
34k views

There are stopped jobs (on bash exit)

I get the message There are stopped jobs. when i try to exit a bash shell sometimes. Here is a reproducible scenario in python 2.x: ctrl+c is handled by the interpreter as an exception. ctrl+z ...
3
votes
2answers
425 views

how do I reference a variable in fish shell with a default fallback

What is the fish shell equivalent to the following bash: echo ${TEST:-1} In bash this would print the value of TEST if there was one, or 1 if there was not.
2
votes
4answers
90 views

Why . /home/Desktop is incorrect and ./Desktop is correct?

I'm learning about Linux, started yesterday. I have a question which I couldn't answer from my book or Google. What is the difference between ./ and / in the shell? I'm asking this because when I ...
67
votes
9answers
68k views

How to add a newline to the end of a file?

Using version control systems I get annoyed at the noise when the diff says No newline at end of file. So I was wondering: How to add a newline at the end of a file to get rid off those messages?
2
votes
1answer
27 views

Reading keypresses in shell using trap and Unix signals

I am trying to grasp a fairly involved Unix shell (tested in bash) function that listens for keypresses. The full code can be found here. The part I am having trouble understanding is the purpose of ...
0
votes
2answers
50 views

Can not execute command with root in a remote Linux host

I try to migrate shell code to Python fabric code. The issue I meets is that Python can not execute command with root in a remote Linux host. Could anyone meet this issue and figure it out? I am very ...
0
votes
0answers
19 views

Issues with Screen - Running Minecraft in a while loop through a screen session

So two days ago I changed my startup scripts for my minecraft server. Problem is, after about 3 hours, the screen for it that I was monitoring "mc" vanished and refuses to list when using -ls. The ...
1
vote
1answer
34 views

Shell read script for sftp

I have this working: % cat read.sh !/bin/sh file=list.txt while read line do echo "$line" cut -d' ' -f27 | sed -n '$p' > file2 done < "$file" % cat list.txt sftp> #!/bin/sh sftp> ...
3
votes
4answers
12k views

How to login as root from Bash and do stuff

This is my simple bash: cat test.sh #!/bin/bash echo "hello" su - root -c /path/to/script.sh <<EOF password EOF whoami echo "good bye" But I get this error: ...
1
vote
2answers
155 views

What is difference between pbrun and sudo command?

What is difference between pbrun and sudo command? I have seen people executing pbrun sudo su - what this means? I know su -, it will try to switch to root user. What speciality pbrun gives to sudo ...
4
votes
5answers
87 views

command which works like ~ (tilde) symbol to represent some directory

cd ~/scripts. This will go into scripts directory in my home. Similar to this, I want some "alias" kind of setting, which will allow me to enter some other directory so that, cd xxx/mywork -> will ...
21
votes
7answers
4k views

how to glob every hidden file except current and parent directory [duplicate]

I want to glob every hidden file and directory, but not the current (.) and parent directory (..). I am using bash. Observe current behaviour: $ ls -a . .. ...a ...aa ..a ..aa .a .aa .aaa ...
0
votes
1answer
33 views

Take output field data string into variable

I want to grep for some specific lines from a log file, and then capture a specific part of that output in a variable and use it in other commands. The grep command I have is the following, where $1 ...
2
votes
2answers
951 views

How to convert a group of video files using FFMPEG?

I have several video files in a directory and I want to convert all of them into other video formats. Is there any way that I can convert all of them in just one go using FFMPEG. I mean without having ...
1
vote
4answers
179 views

How to set the process won't be terminated when the terminal stops

[Edit] Make it simple. I invoked java xxx... on Machine A using putty to connect from Machine B. However I cannot reach Machine B. How can I connect Machine A from Machine C to set the running ...
28
votes
4answers
14k views

How can I make iconv replace the input file with the converted output?

I have a bash script which enumerates through every *.php file in a directory and applies iconv to it. This gets output in STDOUT. Since adding the -o parameter ( in my experience ) actually writes ...
1
vote
2answers
43 views

Aliasing using for or while loop in .bashrc

Can I use a for or while loop when I have similar pattern in the aliases that I put in my .bashrc file? For example, I have: alias c0='ssh computer-1-0' alias c1='ssh computer-1-1' alias c2='ssh ...
1
vote
4answers
210 views

Wildcards for filepaths aren't working in grep [duplicate]

I need to grep words like these: ABC-DEF AB2-DEF AB3-DEF AB-DEF So I was trying: grep AB*-DEF grep -w -AB*-DEF grep -w AB*DEF But neither of them are working. Please help.
3
votes
3answers
43 views

How can I list every port serving a web page

I have a number of servers, all with various HTTP(S) services accessible on a variety of ports. It's incredibly difficult to keep track of which service is available under which host and what port. ...
2
votes
1answer
28 views

Can not access my external hard drive.

I am fairly new to Linux and have been trying to move some files around with terminal on my external hard drive but I can't seem to get it to work. I am using a generic external hard drive with a ext4 ...
2
votes
1answer
38 views

xargs not prompting after each line

I want to know the size of all the data files in my directory. I tried using the following command. The file names all start with data_. find . -name 'data_*' -type f | xargs ls -sh -n1 -p I do ...
4
votes
3answers
46 views

Why can't I open a shell from a pipelined process?

I've condensed my problem into the following code: #include <stdio.h> int main(){ char buffer[256]; printf("Enter input: "); scanf("%s", buffer); system("/bin/sh"); ...
0
votes
1answer
77 views

Ubuntu changing shell on me

This Ubuntu machine is showing errors when I start a new terminal. The problem is this: When bash completion is sourced (. /usr/share/bash-completion/bash_completion) the shell taking place is not ...
1
vote
1answer
62 views

Using MPI with a .sh script?

I am a beginner with Unix and MPI. I have a runPR.sh script as below DIR=/directory/buildagain/bin/Project FILELIST=$1 while read FILE do echo "Processing ${FILE}..." ./makeInp.sh ...
1
vote
1answer
27 views

Restrict ssh access per user based on conditions

Is there a way to restrict a user to only use ssh to connect via SFTP, but disallow that same user to login to a secure shell terminal? I only want the user to have the ability to connect by an SFTP ...
1
vote
2answers
26 views

Separate bashrc file for ssh sessions to avoid Unison Errors

Recently my Unison started throwing up some strange error whenever I tried to sync between my laptop and my PC. I realized that I had added a line in bashrc that would print my pending tasks whenever ...
1
vote
1answer
59 views

Shell intervals using awk

I have a file a 10:10 10:30 b 12:15 13:15 c 16:54 17:54 and I need to enter interval for example 10:15 so my output should be a 10:10 10:30 How I need to do that using awk?
7
votes
2answers
12k views

Why does Ctrl-D (EOF) exit the shell?

Are you literally "ending a file" by inputting this escape sequence, i.e. is the interactive shell session is seen as a real file stream by the shell, like any other file stream? If so, which file? ...
1
vote
2answers
1k views

How to run java service as a non-root user on CentOs 6

I have a script that starts a Java application as a service on CentOS 6: #!/bin/sh # chkconfig: - 80 20 SERVICE_NAME=cn4server PATH_TO_JAR=/usr/local/share/myserver/cn4server.jar ...
1
vote
1answer
46 views

delete non important characters from command output

the version command in my Linux machines display the following output version Red.Hat.OS. release..........5.5 APP.Release.............4.2.0.0-02 how to remove the middle "." dot character ...
-1
votes
1answer
23 views

How can I execute and export in a single shellscript

I have two shell scripts. $ cat java_alternative_7 #!/bin/sh sudo update-java-alternatives -s java-7-oracle $ cat java_home_7 #!/bin/sh export JAVA_HOME=/usr/lib/jvm/java-7-oracle It's simple that ...
2
votes
2answers
58 views

Reliably identifying the path to the directory containing the running script

There are plenty of answers in SO to address this question: Can a Bash script tell what directory it's stored in? Unix shell script to find out which directory the script resides? And there are a ...
3
votes
1answer
76 views

difference between /bin/bash and “.”

Env: Ubuntu 14.04 I have a file called bc on my home folder. The whole content of the file is func() { local a b=() echo $0 } func Note there's no #!/bin/bash at the beginning. Then, if I ...
10
votes
1answer
146 views

Track certain parameters on some command

Let's say that I have a command git branch (always with a couple of words) for example. What I want is to keep track of when this command is executed with arguments. For example, if I execute the ...
1
vote
1answer
14 views

When not started from a terminal, Emacs does NOT pick up the SSH_AUTH_SOCK environment variable

When I don't start it from a terminal, Emacs 24.5.1 (compiled from source) doesn't pick up my environment variables. In particular, to "import" the environment variables from shell, I have in my ...
0
votes
2answers
204 views

How to format xml attributes, not just elements

How do you format an XML document to make it easy to read element attributes? I have a xml based webservice that returns one or two elements, but with hundreds of attributes. As I'm doing ...
4
votes
4answers
579 views

How do I pass a comand-line program a list of files from a directory?

I am trying to upload documents to my Microsoft OneDrive account using python-onedrive. The command I am using is this: onedrive-cli put Long\ Filename\ 1.jpg onedrive-cli put Long\ Filename\ 2.jpg ...