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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28 views

Out-putting the results of a nested for loop to a file in bash

I am new to bash and I have been attempting to create a file out of my loop in bash , I was successful in generating the file with the following code for ((i = 0; i <= 5; i++)); do for ((j = i; ...
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votes
1answer
34 views

how to write own shell that works with ssh

I tried several tutorials I modified usermod -s shell path_to_binary username it does not work thru winscp, but works if use from Ubuntu terminal I want to own shell, where I can control over ...
1
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0answers
8 views

Wacom Linux xsetwacom Attach Shell Script to Buttons

Using Inutos Pro with Manjaro. Would like to attach a shell/bash script to one of eight buttons. Script would be something along the lines of 'firefox'. Can xsetwacom do this?
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0answers
13 views

how to get a “parent-child” relationship with tmux panes and windows

Essentially I'm trying to mimic fork when I split a window or create a new one from an existing tmux session. For example lets say you enter a shell in gnome-terminal and then launch a new gnome-...
1
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3answers
37 views

How to pick oldest file in a folder from directory [duplicate]

I had n number of files are there in my ../in/ directory. From those files I want the oldest file to process and send it to the ../complete/ directory. The remaining files are sent to the ../error/ ...
2
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2answers
25 views

When using popd, how to push the current directory onto the stack?

When using popd, how to push the current directory onto the stack?
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2answers
54 views

Why is $ the default symbol for a user shell and # the default symbol for a root shell?

Operating a standard bash shell on a server, the PS1 prompt defaults to ending in a $ for non-root users, and # for root. IE: ubuntu@server:~$ sudo su root@server:/home/ubuntu# Why is this?
2
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0answers
46 views

wait bash-builtin burns a CPU at 100 percent

Occurs at least on GNU bash version 4.3.42 x86_64 && GNU bash version 4.3.11 x86_64 I use sleep & wait $! instead of a simple sleep for getting an interruptible sleep by a signal (as ...
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votes
1answer
35 views

Gather data from 100 AWS servers [on hold]

I have 100 servers running on AWS. I need to easily get how much data each user on the remote systems are using and output it to a text file. How could I best accomplish this?
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votes
1answer
57 views

Problem Counting the lines of a text file

I want to be able to get the number of non-empty lines in a text file. Suppose I have num.txt with the contents: 10 10 12 15 24 31 32 Here there are 8 lines, with only 7 that are not empty. How ...
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votes
0answers
15 views

How to boot tablet from usb [migrated]

I need to boot my tablet from usb stick where my windows 10 install files are stored. There are no boot settings, I can access only UEFI shell see: That usb is blk0 and blk1 (when i unplug they ...
3
votes
2answers
161 views

what is $$ in bash? [duplicate]

there is a script I evolved with it, it has line of command like below : mytemp=`echo ${sourcedir}|awk -F/ '{printf "/%s/tmp",$2}'`/`basename $0`-$1.$$ at the last of the command we see $$ that ...
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2answers
40 views

Can I use a shebang to have a file source itself into current bash environment?

I have a growing collection of scripts which should be sourced, not run. At the moment they have the shebang #! /bin/cat but I would prefer the have them be sourced into bash when run, in the same ...
3
votes
1answer
56 views

set environment variables from stdout

How can you do the equivalent of piping stdout to 'export'? For background, I have a non-shell script that generates environment variables like so: DATABASE_URL='someurl' MAIL_KEY='key' REDIS_URL='...
0
votes
1answer
42 views

Rename file (Prefix) with full path?

I'd to Prefix my files (.dat) like this : CLY_BIZ_COM_PERD.dat -> 20160622CLY_BIZ_COM_PERD.dat I have tried the following: key=`date "+%Y%m%d"` for i in $(ls /Path/*.dat); do mv ${i} "${key}${i}...
1
vote
1answer
40 views

How to delete tmp files with messy names?

By mistake, I created a lot of tmp files suffix '.bedgraph' in my working directory. How could I delete them? I tried to use rm -rf *.bedgraph but it did not work. MBD_peak_bedfile N?????A???c??XO....
0
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0answers
24 views

Shell script invoking python does not resume on MacOS

I have a shell script that invokes Python on my MacOS. After that invocation completes successfully, the script execution is not continued by terminated: curl "https://s3.amazonaws.com/aws-cli/...
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votes
2answers
42 views

How to add a column of numbers to a array data file

I have a data file with two columns of numbers: input file 4.182 4.1843 4.184 4.2648 4.2281 4.0819 4.2204 4.1676 4.0482 4.1683 4.0156 4.2895 4.4504 5.2369 4.3776 4.4979 4.3797 4.1372 4....
2
votes
2answers
80 views

BASH: Using awk to filter unique lines results in 0 length array

Note: Thank you to Jeff Schaller and steeldriver. But as neither posted as an answer, I'm not sure how to mark as solved. I now have a better understanding of pipes/subshells. I'm pretty sure I once ...
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votes
0answers
21 views

How can i parse the data using multiple delimeters?

Input data is 61418406721,61407219329 username=elsupport@abc.com.au password=clas2012 text= Clas SGB QLD&WA Report - Prop Appl 0 $0.00M. Prop Approvals 0 $0.00M. BMS Appl 0 $0.00M. BMS Approvals ...
1
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5answers
50 views

How can I use the rename command to fix these file names?

I'm trying to change files that look like 01 Track name.mp3 into 01 - Track name.mp3 So far my futile attempts were rename '0. ' '$&- ' *.mp3 rename 's/0. /$&- /' *.mp3 rename '/0. /' '/$&...
5
votes
3answers
576 views

Duplicate file x times in command shell

I try to duplicate a video file x times from the command line by using a for loop, I've tried it like this, but it does not work: for i in {1..100}; do cp test.ogg echo "test$1.ogg"; done
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0answers
23 views

Syntax Error in Do-Loop

So I wrote this bash script, but I am getting a Syntax error: for word in $(<textFile.txt) do java --classpath=$CLASSPATH:/path/to/jradius-client.jar net.sourceforge.jradiusclient....
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2answers
40 views

Defer variable expansion to subshell

My service uses environment variables extensively for configuration (mostly because it's really easy to inject those into a Docker container). I also have some maintenance scripts that I can run ...
0
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2answers
45 views

Read a file using shell script and make 2 new files based on Name of item

I have below file with me :- ====== 20160606:034441 ====== Mango(Test) TestName MangoT Row 0 Season N Name Safeda Location Delhi ====== 20160606:034441 ====== Mango(Result) TestName ...
4
votes
3answers
304 views

Using `find` on not existing directory

Is there a simple way to make this silently do nothing, if /my-directory does not exist? find /my-directory -type f -mtime +14 -print0 | xargs -r0 rm Versions: find: GNU findutils 4.5.10 bash 4.2....
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vote
2answers
49 views

Make the 1st column as header and list its corresponding values using shell script

I have a large file contents are as shown below :- Quantity 20589 Quantity 12297 Quantity 100346 Quantity 0 Quantity 141999 Quantity 23662 Quantity 551071 Quantity 72917 ...
1
vote
3answers
44 views

Move files by reading their file names to different directories

I need to move files by reading their names. I have to move system generated files and the names include a time stamp. I need to move the files by reading the file name by month. If the file name ...
0
votes
1answer
74 views

Explanation of sed in shell script

I found a snippet of code online that would actually help with creating the frequency of each word in a text file however I would like someone to explain exactly how it is doing so Especially the ...
0
votes
1answer
28 views

What is “All shells and programs that use exec*p library calls handle searching”?

I came across this sentence in the following documentation but couldn't understand it, and the link to one of its terms appeared broken to me. Can someone help? All shells and programs that use ...
0
votes
2answers
37 views

cat doesn't join my files when I run inside script

I'm doing a restore backups script, and when I try to join files which are splitted, cat prints that error: cat: fullbackup_mrbsNuevo_15_6_2016.tar.gz.*: No such file or directory The line that ...
1
vote
1answer
131 views

How to sed -i '`[echo $var]`i word' file?

Code: pos=2; printf "Masi \nwas \nhere" > /tmp/1 sed -i '`echo $pos`i huhu' /tmp/1 Expected output: Masi huhu was here Current output: sed: -e expression #1, char 1: unknown command: ``'
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votes
1answer
41 views

using shell script to posting Json body to curl by loop

Hi I have many Json file which need to be post to curl. so can some one help me how to write loop for the same? am trying this way for FILES in $~/network_map_ingestion/networkmap/data/consolidation ...
-1
votes
1answer
45 views

How can I pass the file names to xargs and truncate them? [closed]

I have to write a script which will ssh into servers and truncate log files My script is #!/bin/bash for server in $(cat c10_servers.txt) do ssh $server " ls /var/log/hello grep -i hello.log. |...
10
votes
1answer
277 views

How does ksh93 avoid forks in command substitution

Given cmd='fun(){ echo "$@"; }; fun $(fun $(fun hi))' shells tend to need to make 2 forks to make it happen strace-f(){ strace -f "$@" 2>&1; }; for sh in dash bash zsh ksh; do ...
3
votes
1answer
34 views

Capture output (sdout/stderr) of SSH port forwarder

I would like to store the error below in a variable: ssh -M -S /invalid/path/forwarder.socket -fnNT -Llocalhost:6301:remote_server:22 proxy_server muxserver_listen bind(): No such file or directory ...
0
votes
1answer
40 views

How do I find and list folders with a specific folder name, containing files modified recently?

I have a set of folders that are regularly updated, which I would like to regularly parse through and update to a simple text file list. This list gets used with rsync so I shorten the file names ...
1
vote
1answer
40 views

Shell - PTS/0 Suddenly Changed to PTS/1 Why did it happen and how to change it back?

Whenever I enter the who command in the SSH I see the PTS/1 after my username. Two days ago it was still PTS/0. Is this called the TTY? How do I make it PTS/0 again? Also the path now is /dev/pts/1 ...
0
votes
1answer
32 views

System messages in vim

O/S: Arch Linux (Kernel 4.3.3-2-ARCH) While editing files with VIM 7.4 it occassionally happens that system messages appear on the screen, ruining my workflow but obviously not altering the ...
2
votes
1answer
134 views

specify shell for ssh session

I am logging to a remote server via ssh as user www-data. User www-data on the server has his default shell set to /bin/sh, and when I log in, I get dash as my shell. I can then type bash and get bash ...
1
vote
2answers
63 views

Wait until a process comes back from sleep

script.sh is run by run.sh N times in parallel. For N=1, the script.sh process is set to sleep 30-45 seconds before it actually starts. How can I order ALL script.sh instances for N>1 not to start ...
12
votes
1answer
250 views

Setting temporary bash aliases when entering a folder

Sometimes I like to have very customized bash aliases and maybe keybindings when I enter on a folder (can be a project where I'm used to type lots of commands from CLI). Lets suppose when I enter a ...
0
votes
1answer
39 views

Difference between set variable “value” and set variable value?

What is the difference between the following 2 examples in a shell script: set variable1 "value" set variable2 value
1
vote
2answers
62 views

Copy files that are created today without FIND command and SFTP to another server

I have a directory with 'n' number of files in it. I am trying to write a shell script which will list only the files created on the particular day the script is running, and will use sftp to move the ...
0
votes
1answer
37 views

find: missing argument to '-exec'

this is my first post, as I am completely new to the programming world. Basically I'm taking a UNIX class and I have an assignment asking me to check the size of regular files in my home directory for ...
5
votes
1answer
672 views

When files are being moved are they stored in a memory?

When I move a file using the mv command, is this file first read, fully cached into a memory and then saved as another file? Or is it the same as writing while read line; do echo "$line" >>...
0
votes
1answer
58 views

Curl a string with whitespaces and characters in it? [duplicate]

I'm trying to create a "simple" script that I'm going to use to create some documentation for Unix/Mac machines. I've successfully received the information I need, but it seems like I can't send it ...
5
votes
2answers
348 views

nested double quotes in highly-voted one-liner

A StackOverflow answer with > 3.5K votes features this one-liner for assigning to DIR the directory of the current bash script: DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )" I'm ...