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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0
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2answers
38 views

Run script on non-full bash-login invoked as “sh”

Good day I'm currently trying to modify my terminal to have the prompt displayed in a different colour than the whole rest of the shell, and I would like to make it white for normal users and red for ...
0
votes
1answer
36 views

shell sleep until next full minute

To execute a script on the next full minute I want to tell the sleep command to sleep until the next full minute. How can I do this?
1
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2answers
33 views

How to run a long running grep, pipe the result into less and put everything into background?

I often find myself in the situation where I need to find a code base for a given symbol like so: find src/galio -not -path './src/stapi-sdk/apilib/* -regextype posix-extended -iregex ...
1
vote
1answer
52 views

Output different lines when comparing two files

I have two text files with the same number of newline terminated strings. The lines in the two files correspond to each other. The lines in each file individually might be repeated. I would like to ...
2
votes
2answers
1k views

Using sudoers to allow php to run command

I am trying to get my php page to run this command: shell_exec("sudo /home/xbian/433Utils/RPi_utils/codesend {$num}"); So I added this entry to my sudoers file with visudo: www-data ALL=NOPASSWD: ...
2
votes
1answer
90 views

About executing shell script

Suppose I have a shell script file foo.sh. I can do chmod + x foo.sh and change it into an executable file. In Kernighan-Pike: Unix Programming Environment (UP) they show that after this typing ...
0
votes
2answers
77 views

Recursively remove files with idx > 10,000

The problem In the current working directory I have several (very many) folders and some of them have lots (like 100,000+) of files inside. My goal is getting just the folder with 10,000+ files and ...
29
votes
1answer
2k views

Does 'rm .*' ever delete the parent directory?

The expression .* is expanded by bash to include the current and parent directories: $ ls -la total 2600 drwxrwxrwx 2 terdon terdon 2162688 Sep 10 16:22 . drwxr-xr-x 142 terdon terdon 491520 Sep ...
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votes
4answers
59 views

How to remove line based on Delimeter in perl / Shell?

Can anyone help to remove the line in file based on delimeter(Comma), Incase if line contain less number of columns or Bad records , Need to delete those. Input File: a,b,c,d a,b,d,f c,d a,v,b,h ...
0
votes
0answers
17 views

Moving Informatica data(directories) from one unix server to another unix server

Can we migrate directories from one unix server to another unix server, without the need of installation of Informatica softwares on the new unix server? If yes, then will there be any change in the ...
26
votes
7answers
41k views

How can I get the size of a file in a bash script?

How can I get the size of a file in a bash script? How do I assign this to a bash variable so I can use it later?
15
votes
2answers
9k views

bash multi line command with comments after the continuation character

Consider echo \ # this is a comment foo This gives: $ sh foo.sh # this is a comment foo.sh: line 2: foo: command not found After some searching on the web, I found a solution by DigitalRoss on ...
1
vote
2answers
473 views

Script to su -c into a screen is not working as intended

I'm working on a script that will allow me to load up a screen from a user via sudo and su -c. However, when I use it, it will just show the shell of the user: sudo su -c "script /dev/null; screen -r ...
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votes
1answer
41 views

Some commands not working in bash script

I'm using Ubuntu 14.04.02 32bit. On doing some shell programming, I found out that running the script through the sh command sometimes cause errors. Is it because the sh command is invoking the ...
22
votes
6answers
53k views

Is there a way to see details of all the threads that a process has in Linux?

For Windows, I think Process Explorer shows you all the threads under a process. Is there a similar command line utility for Linux that can show me details about all the threads a particular process ...
-3
votes
2answers
65 views

echo $HOSTNAME result become key to a variable

Property server1=abc,def,ghc server2=xyz,tes,iuy #!/bin/sh echo $server1 abc,def,ghc echo $HOSTNAME server1 with those info above, I want to output the output "abc,def,ghc" in a test variable. ...
1
vote
1answer
39 views

Relation between system calls and shell commands/utilities

In POSIX, Does a system call function often but not always have a command or utility in shell? Is there some rule of thumb about what kinds of system calls have corresponding commands or utilities ...
12
votes
2answers
11k views

Parse html on Linux

I have a couple of hundred html source code files. I need to extract the contents of a particular <div> element from each of these file so I'm going to write a script to loop through each file. ...
4
votes
1answer
59 views

Source Bash automatically in terminal

How can I automatically source a particular bash script when I open a terminal window by right clicking somewhere and choosing "open in terminal"? For example, every time I open a terminal I need to ...
5
votes
5answers
547 views

Getting the pid's of a program line by line

I can find the pid's of my program instances by issuing command like this: pidof avconv Which is giving me results 16616 16283 16279 16198 16175 16035 15073 14049 4922 But how can I output the ...
7
votes
4answers
4k views

How to embed a shell command into a sed expression?

I have a text file with the following format: keyword value keyword value ... Where keyword is a single word and value is everything else until the end of line. I want to read the file from a shell ...
3
votes
4answers
554 views

How can I turn the behavior of `gedit sOmEtHiNg & disown` into the default behavior when calling gedit from the command line?

When I gedit files from the command line, it's always locking the terminal, and I'm tired of explicitly commanding a detached process for it. I tried to alias gedit as something like gedit $* & ...
2
votes
4answers
125 views

How can I find the program I'm hiding in bash

Say I have PATH="home/bob/bin:/usr/bin". I am writing a bash script /home/bob/bin/foo that will do some munging and then call /usr/bin/foo. Of course I want to be able to use this script on ...
0
votes
1answer
95 views

How to convert Ubuntu init script to Amazon Linux AMI init script?

I had a Ubuntu based Amazon EC2 server where I was running my java based application. For this I had written a init script which was running perfectly and as follows #! /bin/sh # set the environment ...
4
votes
1answer
53 views

How to make sure the $var variable in expanded in “$varsomething”?

I'm trying to run something like this for n in 1 2 3 4 5 6 7 do run_this_command whatever.$nx$n.in done The files are named as whatever.1x1.in, whatever.2x2.in, ...
2
votes
1answer
27 views

passing tmux variable into shell-command in tmux.conf

I'm trying to edit my bottom left status section of tmux. I would like it to show Session: #{session_name} The current maximum length for this string is set at 20 using this setting ...
5
votes
7answers
428 views

Turn list into single line with delimiter

I have to take a list (loads) of IP addresses in this format: 134.27.128.0 111.245.48.0 109.21.244.0 and turn them into this format with a pipe in-between (IPs made up) 134.27.128.0 | ...
7
votes
1answer
9k views

Single command to login to SSH and run program?

Is there a way to structure a single command to login via SSH to a remote server and run a program on the remote login shell? In the OpenSSH manual, it reads "If command is specified, it is executed ...
0
votes
1answer
1k views

How to execute Netscaler commands through a remote machine via SSH connection

I have been trying to execute some NetScaler commands like "bind" & "unbind" through a Linux Box via an SSH Connection. Now the Problem is, Manually we are able to enter & execute commands on ...
11
votes
2answers
756 views

What is DISPLAY=:0?

What is DISPLAY=:0 and what does it mean? It isn't a command, is it? (gnome-panel is a command.) DISPLAY=:0 gnome-panel
1
vote
1answer
66 views

Why is this simple bash script throwing an error on if/then/else? [closed]

If I try to run this script: clear echo -n "please enter a value" read num if [ "$num" -eq 8 ] then echo "you entered 8" else echo "the number you entered was not 8" I get the ...
4
votes
2answers
358 views

while: command not found

I'm trying to do this as an April Fool's prank: make a linux machine display a message in the shell every few seconds. My thought is to achieve this by starting an infinite loop that runs as a ...
6
votes
5answers
15k views

Disable user shell for security reasons

We have several user accounts that we create for automated tasks that require fine-grained permissions, such as file transfer across systems, monitoring, etc. How do we lock down these user accounts ...
12
votes
9answers
3k views

Is using “while true” to keep a script alive a good idea?

I'm just jumping into unix from a different world, and wanted to know if while true do /someperlscript.pl done The perl script itself internally has a folder/file watcher that executes when ...
1
vote
3answers
136 views

Shell expansion for arguments?

For example: mkdir ~/{1,2,3} Creates directories ~/1, ~/2, and ~/3. It equates to: mkdir ~/1 mkdir ~/2 mrdir ~/3 But, using the same syntax in the case of CMD < argument > : brew {install, ...
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votes
1answer
26 views

extracting non hidden files in shell scripting [closed]

In shell scripting while listing a directory need to extract non hidden files need to remove upload, archive and download example : upload archive download simple data final .bash_logout ...
0
votes
2answers
25 views

Dividing up columns and submitting the value as stdin into a seperate program within a script [closed]

I currently have two programs written in C named "remove" and "calculate". When I call ./remove it removes some data from stdin. When I call ./calculate which takes in an argument and also data from ...
1
vote
1answer
38 views

Is it possible to establish a Socket session (between Server and Client) using shell commands ?

From what I read (only the very outline, i do not know C Language) a Socket session is established between a server and a client by calling functions for both of them in a certain order. It starts ...
1
vote
4answers
79 views

find: missing argument to `-exec'

when I'm trying to use this command var1=`sudo -u psoadmin -H -s ssh daill_scp@files.dc1.responsys.net find . -maxdepth 1 -type f -mtime +14 -exec ls -lh \{} \; | awk '{print $5, $9}'|egrep -v ...
72
votes
6answers
44k views

Allow setuid on shell scripts

The setuid permission bit tells Linux to run a program with the effective user id of the owner instead of the executor: > cat setuid-test.c #include <stdio.h> #include <unistd.h> int ...
2
votes
1answer
66 views

Printf formatting with variable format - what does this var reference?

I am experimenting with printf formatting in bash and I ran across this piece of code: #/bin/bash divider=============================== divider=$divider$divider header="\n %-15s %8s %10s %11s\n" ...
2
votes
0answers
44 views

List all btrfs filesystems and subvolumes in shell

Is there a convenient way to get information on all btrfs filesystems subvolumes without resorting to C, i.e. in POSIX shell ? /sys/fs/btrfs contains info only on filesystems, nothing on subvolumes, ...
1
vote
1answer
30 views

How to move directories based on the output of rhash (CRC32 check of .sfv) with bash/perl?

My idea, is to move the CRC-check OK folders (albums) into a lets say "complete+CRC_OK" folder with a script once per day in cron. I would need to put the rhash command in a loop with number of ...
16
votes
4answers
590 views

How can I implement a circular flow of data among interconnected commands?

I know of two types how commands can be connected with each other: by using a Pipe (putting std-output into std-input of the next command). by using a Tee (splice the output into many ...
5
votes
6answers
4k views

How to insert the content of a file into another file before a pattern (marker)?

File1 contents: line1-file1 "1" line2-file1 "2" line3-file1 "3" line4-file1 "4" File2 contents: line1-file2 "25" line2-file2 "24" Pointer-file2 "23" ...
3
votes
2answers
52 views

GNU Parallel: Event not found (!~)

About my code: get all .txt files for each file, execute the awk command. All files are processed in parallel if colum 3 does NOT contain "needle", write line to file Result: -bash: !~: event ...
0
votes
1answer
23 views

Aliasing a command with parameter supplied to another command

Namely: I want to alias tail -f to less +F but let tail with any other parameter supplied work the same way as before.
0
votes
0answers
35 views

echo `“hello terminal” > /dev/terminal` - works for /dev/tty[2-5] but not for /dev/pts/n

I'm trying to get to know the input output systems of unix/linux systems better. Since terminals and devices are implemented to interface as ordinary files, I assumed I could on any desired terminal ...
1
vote
1answer
60 views

How to know which platform I am using in lubuntu, ubuntu or kubuntu

I need switch script in between lubuntu, ubuntu, and kubuntu. How can I know which platform the script is running in? Because uname/lsb_release never show different in those 3 releases Lubuntu$ ...
1
vote
2answers
120 views

Why doesn't “rm -rf ./” delete anything?

The command rm -rf ./ does not do anything in a directory full of sub directories and files. Why so? Isn't -r supposed to go recursive? To add more confusion, it even prints an error message ...