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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Automate Transferring Files from Windows to Unix through SCRIPT

I have to make an ** AUTOMATED script which transfers files from Windows to Unix through FTP**. I need to do this file transfer process simply by running the script once unlike doing it manually every ...
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1answer
18 views

Get value of environment variable in for loop

I have several environment variable pam_branch app_branch worker_branch I use an array to define different projects and I want to get the values of these env var by rebuilding them in a for loop ...
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1answer
61 views

Execute sh with parameters in bash

Hello I am newbie in bash and I am coding a daemon to execute a service. The syntax is ./ctlscript.sh start. When I execute service openproject start it should run this command, but it runs ...
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2answers
127 views

Get a refreshing list of running specific processes

I want to monitor running python processes with VSZ, RSS %MEM, %CPU etc. One of my priorities is a list refreshing every X seconds. I managed to come to the point of obtaining a refreshing list of ...
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4answers
81 views

Is it possible, with `sed` or otherwise, to apply a regex transform to an input stream that may not contain newlines?

I have a shell pipeline that contains a sed expression: source | sed -e 's:xxxxx:yyyyy:g' | sink It works but it has a latent flaw because sed works on whole lines. This means that the sink will ...
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2answers
31 views

Escaping double quotes in string

I have a string message which contains data in double quotes. I need to put \ in front of every double quote how can u do it in shell ? I used Perl and it works fine, but I'm looking for sh command: ...
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1answer
50 views

Variables outside of while loop

I am trying to echo the variables $f1, $f2, etcetera, outside of the while loop shown below. From what I understand, the scope of the variable is not correct. Therefore I tried a few of the ...
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1answer
12 views

Convert Asyncronus reset into syncronus reset in verilog

I have multiple Verilog RTL files in which we have use asynchronous reset. But I want to convert asyncronus reset to synchronous reset. Before: always @ (posedge clock or negedge reset) After: ...
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2answers
159 views

How to send all output to `logger` in POSIX shell?

I'd like to log standard output and standard error separately in .xprofile using logger. In Bash I think that would look something like this: exec 1> >(logger --priority user.notice --tag ...
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3answers
71 views

Modify multiple files in different folders with one command?

I have a file abc.txt in the folder /etc/zyz/ and also in a few sub folders /etc/zyz-1/ /etc/zyz-2/ How can I modify all of those files with a echo command for example (all named abc.txt) in every ...
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1answer
24 views

Filesize in for loop

I am trying to get the filesize of each file in a folder by using stat in a for loop. I know why the following is going wrong, but I don't have enough knowledge yet on how to fix this. #!/bin/bash ...
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1answer
38 views

Why is my CD command not working on a home-built shell? [duplicate]

I have written a very basic shell in C. It reads the input, then runs it using system(lineCopy); (lineCopy being a copy of the input). All commands will run fine in it, other than cd. When I try to cd ...
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2answers
34 views

Piping contents of multiple files between programs while keeping contents separate

I would like to read in a number of files and pipe their output to subsequent programs while still maintaining them as individual pipelines of data. program1 *.txt | program2 | program3 folder I ...
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2answers
37 views

Live monitoring of background jobs

I executed a command like this: nohup some_command &. Now this command is in the background. I can see it with the command jobs. Example output: [1]+ Running nohup some_command ...
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1answer
30 views

How to echo makefile variable through Make's $(shell …)

I have a GNU makefile. The makefile has a few tests (around line 65 from the linked file): UNAME = uname MACHINE ?= $(shell $(UNAME) -m) SYSTEM ?= $(shell $(UNAME) -s) IS_X86 = $(shell echo ...
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1answer
43 views

Which are (bash) shell special parameters?

I've found some special parameter with bash starting with $ sign. Example: When I was wandering for exit status I knew about $?, process ID by $$ etc. So, I am sharing this post to know Which are ...
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15 views

Why won't MOTD display output from a Python script it calls outside of /etc/update-motd.d/ unless it's in this directory?

The Situation We're running a headless Ubuntu 14.10 Server to fulfill various needs and tests. I was experimenting with changing the MOTD for SSH sessions via /etc/update-motd.d/ so as to display ...
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2answers
101 views

Free or cheap shell (i.e., platform) to run a Linux C program with root privileges (raw socket)

I'm working on a Linux C program that needs root privileges (raw socket). I would like to run it on a host located in the US (I am in EU) to compare results. Is there any free (or cheap) shell ...
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3answers
2k views

Is there ever a good reason to run sudo su?

To launch a root shell on machines where the root account is disabled, you can run one of: sudo -i : run an interactive login shell (reads /root/.bashrc and /root/.profile) sudo -s : run a non-login ...
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1answer
49 views

Why the number is rounded over ssh? [duplicate]

localhost:~ $ df -k / | awk '{print $3/1024/1024/1024}' 0 0.00618061 localhost:~ $ ssh localhost "df -k / | awk '{print $3/1024/1024/1024}'" 01 01
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0answers
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initramfs-tools syntax errors with Heirloom sh

My current system is: $ lsb_release -a No LSB modules are available. Distributor ID: Debian Description: Debian GNU/Linux 8.1 (jessie) Release: 8.1 Codename: jessie with kernel: $ uname -a ...
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2answers
122 views

Which shells don't support dollar-parenthesis expansion, and demand backticks?

The modern recommendation is to use: $(...) instead of the older: `...` mainly for readability and to avoid the need for escaping when nesting. Which shells do not support the $(...) form, and ...
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2answers
42 views

find closest matching folder

What is the best way to sort the results of $ find . -name scripts -type d by the occurrences of '/' and then choose the first result. I want to create a function that would cd down to a common ...
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1answer
17 views

Run .zshrc when passing command via -c

I have a script that runs a command via zsh -c. However, when zsh runs, it doesn't appear to load ~/.zshrc. I understand a login shell flag exists, but even zsh -lc <command> doesn't seem to ...
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1answer
37 views

bash on command event (or shell)

Is there a way to capture all commands executed in a bash or even better in sh? I need a wrapper script that gets called everytime a command is executed. Like when I type cd /home/ I want my ...
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1answer
26 views

Restart bash from terminal without restarting the terminal application (mac)?

I've looked around and bit for an answer to this question but I don't seem to find it (which is weird). My question is, is there any simple way to restart the bash session from within the terminal on ...
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7answers
2k views

How can I make a script to count up by fives?

I was trying to make a very simple bash script to list all of the multiples of five between 375 and 3500 (375, 380, 385...). One thing that I tried and didn't work is: for i in {375..3500} do ...
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1answer
40 views

du reports directory size as much bigger than the sum of its contents

Running du -shc * in the top directory gives 110G for a particular folder, whereas running the same command inside that folder gives a total size of 11G. How is that possible? Platform Details: OS: ...
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3answers
54 views

Pipe output of one command to two others [duplicate]

I need to pipe the output of one command to two other commands. cat filename.txt | tail -n 1 cat filename.txt | wc -l Since the file is huge I want to avoid reading it twice. I checked tee command ...
2
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0answers
41 views

shell operation within makefile [on hold]

I have the following line in my makefile: var := $(sort $(foreach m,$(libs),$($(m)-objs))) which I change in a way it now use sort from shell: var := $(shell echo $(foreach ...
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1answer
49 views

Bash script strange behavior - script does not act as manual commands

So, this is strange. When I manually run commands it all works fine, but when I run a script with identical commands, I get strange error output. This is what I run: lxc list; for elem in ...
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1answer
38 views

How to rename or delete an alias permanently from system?

I have created one alias in my system, printf "%s\n" "alias shh='sqlplus hfdora/hfdora@hfd2" >> ~/.kshrc Now, I want to change the alias name from shh2 to shh Also, how to delete other ...
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2answers
28 views

Call a script for another script, but don't exit the parent if the child calls exit

first.sh: #! /bin/ksh echo "prova" . ./second.sh echo "ho lanciato il secondo" . ./third.sh echo "ho lanciato il terzo" second.sh: echo "sono nel secondo script" dosomething1 exit $? If ...
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2answers
49 views

cut string on last delimiter

I have a filename like a.b.c.txt, I want this string to be splitted as string1=a.b.c string2=txt Basically I want to split filename and its extension.I used cut but it splits as a,b,c and txt. I ...
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2answers
47 views

Returning an variable from a function

I have the Linux script from bellow. I can get to return from the method decrypt nothing in order to unzip a file. The method decrypt sends a string with the name of a zip file. Please give some ...
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1answer
59 views

replace the the first line of all .sh files in a folder

Create list of all .sh files in current folder. Check first line of each file in this list and if file starts with #!/bin/sh then replace that with #!/bin/bash. Only modify files that have #!/bin/sh, ...
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0answers
16 views

Adapt text lines to fixed length [duplicate]

With the shell command fmt -w 30 myfile it is possible to truncate the myfile lines so that their length is at most 30 characters. The result is however not a justified file: some lines will be ...
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1answer
61 views

Find the number of files with sizes

Find the number of files with sizes > 100KB in /, /bin, /usr, /usr/bin and /usr/sbin directories and output them in a two column format with the name of the directory and the number of files.
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1answer
26 views

remove _ as prefix from the multiple files in a directory in Soalris [duplicate]

I have to remove _ which is as prefix for a file. I used: for i in _*.txt; do mv ${i} ${i/#_/''}; done but it does not change the names of the files which has space in between as _abc xyz-abc.txt ...
2
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1answer
78 views

What are the Linux shells that allow network traffic management (sending/receiving data to/from `/dev/tcp/host/port`) via redirectors?

Following this Bash tutorial, I have succeded in obtaining the code of a web page issuing simple commands by using this method: $ exec 3<>/dev/tcp/www.google.com/80 $ echo -e "GET / ...
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2answers
46 views

Seems like some basics are missing from ubuntu…or I haven't set them up?

I can't define a shell variable like so: $a = "hello" echo $a echo a $a a all lead to nothing. Also, this command doesn't work for me: $ echo "HELLO HOW ARE YOU?" | tr '[:upper:]' '[:lower:]' ...
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0answers
16 views

display JPEG Exif header with od (Octal Dump)

there are several command line tools to show Exif header of JPEG images. I wish to see the same info with od (octal dump) $ jhead 1430472877538-0.jpg File name : 1430472877538-0.jpg File size ...
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1answer
56 views

How to execute shell commands in a loop from within a bash script?

I am new to bash and need help badly. I want to write a script which will run on my android phone & perform the following things: echo "1" > /sys/kernel/mm/ksm/run wait for 2 minutes: then ...
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3answers
201 views

How to pass argument with char ( in remote path?

I'm trying to move a file with rsync to a remote location, The file has be be named : DRRS_(H264).mp4 but when I try : rsync -azR output.mp4 user@server.com:encoded/somepath/DRRS_(H264).mp4 it ...
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2answers
133 views

How to generate a random string in a profile alias?

I have an alias in my server's /etc/profile which generates a random directory on command, like this: alias rdir="mkdir -p ./`cat /dev/random | tr -cd 'a-z0-9' | head -c 8`/" But it turns out this ...
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1answer
35 views

Writing an install script for CentOS

Every time I deploy a VPS server, I install VNC server. But every time I have to do this: yum groupinstall Desktop yum install tigervnc-server yum install vnc yum install firefox (etc.) Can I ...
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Why rsyslog leaves the last file in spool directory

Suppose I am using a rsyslog remote server (R1) & have a client box (C1). C1 is configured to sync up and use R1 for logging (over port 514; TCP) The spool directory is '/var/log/rsyslog'. Now, ...
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2answers
24 views

How can I properly escape a string to be passed to a shell with a command argument [duplicate]

How can I properly escape arbitrary commands? For example: sudo -u chris sh -c 'echo "\"leftright\""' The above echos: "leftright" How would I echo out: "left'right" I've tried the ...
2
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1answer
93 views

Finding out what sh is [duplicate]

I am writing a set of scripts that I want to be portable, but I need to know whether sh on the current platform stands for bash, ksh, or ash. Is there a clear way to do it? What comes to my mind ...
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What does a hash key preceded by an exclamation key (!#)mean? [migrated]

See the following script from scala tutorial, What does the !# mean? #!/bin/sh exec scala "$0" "$@" !# object HelloWorld extends App { println("Hello, world!") } HelloWorld.main(args)