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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105 views

Tracking my shell path in Emacs

Not a long time ago, I found the following precious snippet that allows Emacs to track my current directory on any ansi-term buffer. More specifically, if I cd <some/path> from within a ...
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186 views

How do I execute in background / return early?

For reference, I'm using phpseclib to control a remote SSH server using the 'root' account. I have to start/stop a java process which is ran in the background. Stopping works fine with killall java ...
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30 views

Bash Script — ffmpeg not being invoked as expected

I'm working on a bash script to convert my music library to ogg* but executing the right command is somehow eluding me. This is the line that should accomplish it: ffmpeg -i "${file}" -f flac pipe:1 ...
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0answers
98 views

What default shell to use for an SSH user limited to a single command

When limiting a user to a single command via ssh, what default shell should be used for the user? This is a follow up to how can shellshock be exploited over SSH? I have a machine that is running an ...
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52 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, ...
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42 views

Higher-level wrapper for entr or inotifywait

I'm looking for a way to rerun a specific command as soon as any of the files in a subdirectory (perhaps minus selected excludes) changes. Use case I'm working on a project that is self-contained in ...
2
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0answers
42 views

A way to distinguish between interleaved output from two background processes

If I have two backgrounded processes that produce input to STDOUT or STDERR (e.g., two installation scripts), is there an easy way to make these two output streams distinguishable? I guess I can pipe ...
2
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69 views

“Restart” a process in the same terminal?

I put "restart" in quotes because the following question on SO illustrates what I'm trying to do: http://stackoverflow.com/questions/27957091/restarting-a-process-in-the-same-linux-terminal I'm ...
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45 views

How to get the mplayer's single-line playing progress info?

mplayer shows and refreshes a single-line playing progress when playing a media file. A sample result is: A: 17.2 (17.2) of 213.0 (03:33.0) 0.5% And I'm trying to grep this playing progress and ...
2
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0answers
61 views

Is there a difference between double quoting a variable or a whole line in echo

When you type, for example, echo Variable "$var" is not initialised. and echo "Variable $var is not initialised." the front end result is the exact same (as far as I know, at least). But I was ...
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70 views

Read output in `screen` from outside

Suppose I opened up a screen to run some program that outouts some result. Once the program finishes, is there a way to get the result in the screen from outside. For example: I opened up a screen ...
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95 views

How can you get the current terminal line (the one that is still editable by the user)?

I need a way to use the current line which the users typed into as variable for a shell function. my current code, which can be called by ctrl+r zle -N search bindkey "^R" search search () { read ...
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248 views

How to pass multiple commands via pssh and multiple xterms

I'm attempting to open multiple xterms and run a command as an SAP user via sudo using pssh. So far, I'm able to run PSSH to a file of servers with no check for keys, open every xterm in the servers ...
2
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0answers
373 views

How does SELinux / SEAndroid prevent or allow pseudo terminal allocation?

I'm trying to resolve an SSH connection issue on an Android phone running SELinux in "Enforcing" mode. The problem is that any SSH connection that tries to allocate a pseudo-terminal (/dev/pts etc) is ...
2
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0answers
104 views

Segmentation fault with dialog

I'm getting a segmentation fault with the following script when it's more that one child dir past the pwd. The program kills with the error message and I have to reset the shell. For example: I start ...
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0answers
129 views

zsh: Echoing every statement?

I have an odd problem with zsh when I switch between shells in a particular way: Option 1 (works well): I start a zsh shell. I switch to tcsh with /bin/tcsh, and I switch back to zsh with /bin/zsh ...
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0answers
322 views

What happens when you background a function which calls another function?

Question says it all on the tin. Can someone explain to me what goes on here ? I'm trying to find out how to background a process in a script that calls another function and reliably terminate it when ...
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21 views

Is it possible to create aliases that affect services starting?

Currently I have a custom service that executes java in multiple places. I want to be able to add an option to any executions of java this service will spawn (I'm specifying the error log location, ...
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37 views

Shell Script to change user shell

I am writing a script that would be invoked to change user shell. The basic requirement is that once user gets authenticated (e.g: thorough some web application) the script would be invoked to set the ...
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18 views

Setting custom baud rate on console

Just for aesthetics I would like to have my text on my console be displayed at a lower speed. I've tried using things like screen with custom baud rates of /dev/tty1 but it wouldn't work, input from ...
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77 views

Sed regex printing into a file.txt

I'm connected to a MQTT stream, and I filter out the data by entering : mosquitto_sub -d -t +/# 2>&1 | sed -n "/PUBLISH/{s|.*\('.*',\).*|\1$(date),|;N;s/\n//;p}" into the Ubuntu terminal. ...
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66 views

What is the meaning of the string **/* when used with grep?

I came across this picture (below), obviously it is a pun or some kind of allusion incorporating command-line expressions. Frankly speaking I do not understand anything of it except for grep -n. ...
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53 views

Autocomplete issue in bash with equal sign (=)

I am trying to make autocomplete work and wroted a piece of code to demonstrate an issue I faced up: $ cat completion.sh function _completion_command() { compopt +o bashdefault +o default +o ...
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69 views

gdrive -bash: /usr/bin/drive: cannot execute binary file

I am processing hundreds of image files on a weekly basis and gdrive would be perfect for automatically making duplicate copies of the raw images for archive before the originals go through the ...
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28 views

optimisation of bash globs

Looking for a guide to optimising regexp matches in bash. I have a script that loops over a very long list of URLs looking for patterns. Currently it looks a little like the fragment below. Is there ...
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84 views

pkill -P $ID working while kill — -$ID not

I was playing around with creating and killing process groups on linux ( ubuntu ) I am trying to kill a process group and am being driven crazy by the fact that pkill -P $ID works while kill -- -$ID ...
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343 views

Cannot add startup service to openWRT from init.d

I have openWrt installed on a TP-Link TL-WA901N/ND v3. I don't have luci package installed because I don't have enough space, so I can only do thing via cli. What I'm trying to achieve is to create a ...
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282 views

Cannot SSH after switching to Netgear router

I have Comcast Xfinity internet. When I was sent their Wifi router/Cable modem combo box, I was able to use SSH perfectly. However, since the Wifi from the box was weak, I decided to buy my own ...
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620 views

Load a background image or set the background color if Konsole/Shell is running SSH

I want to set my laptop to load an image in the shell's background or set the background color to red if I'm connected via SSH. How can this be done? With a bash function in .bashrc? I have: Set the ...
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136 views

How to start a process chain from the shell

Is it possible and if so how do I: Start a /bin/bash process that is not bound to a terminal from a terminal? Hence, a shell process that shows up in the process tree as init -- bash. (Shells ...
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124 views

Chrome OS: Crosh Window and Hostname

I have a couple of questions regarding Chrome OS: By default Ctrl+Alt+T opens a crosh window within the Chrome browser. I have the Crosh Window extension, which I would like Ctrl+Alt+T bound to - ...
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185 views

Measuring context switches of a LWP gives incorrect results. Why?

I have a Java thread pinned at my cpu core. It is busy spinning and I see through top that it is running fine: %Cpu0 : 0.0 us, 0.0 sy, 0.0 ni,100.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st %Cpu1 : ...
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84 views

Execute commands on TMUX Detach

Is it possible to execute commands on tmux detach? I usually have a rails console and server running in the tmux session, on detach is it possible to automatically end those? Thanks.
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55 views

Merge several files with maximum 1 line difference

Suppose I have the following files: file0.c: int b=NULL; int a=NULL; file1.c: int b; int a=NULL; file2.c: int b; int a=NULL; I am looking to merge the files file1 and file2 to generate the ...
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0answers
429 views

Using node.js and shelljs as interactive shell

Following the answer given at unix.stackexchange.com/questions/58011/is-there-a-javascript-shell That requires me to always execute var shell=require("/usr/local/lib/node_modules/shelljs"); It ...
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239 views

Serial Communication on DD-WRT stty config not sticking

I am attempting to control a serial device (in this case a projector) using a Fonera router with DD-WRT on it. I've got the serial port on the fonera wired through a level shifter and then into my ...
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0answers
359 views

gnome-terminal cmd leaving processes open after closing parent window

The following simple command should demonstrate my issue: gnome-terminal --tab -t "Tab 1" -e "/bin/bash" --tab -t "Tab 2" -e "/bin/bash" This should open a new window with two tabs and an active ...
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0answers
594 views

service command: Failed to issue method call

I downloaded the source of tinyproxy and then use ./configure make make install to install it Then I want to start it, but get errors, like the following: [root@kitty tinyproxy-1.8.3]# service ...
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0answers
85 views

add audio from playing file to microphone stream

I need to add a sound to what the microphone is capturing, is it possible? I started with man aplay and found that I can do aplay -D PCMdevice filepath.wav so then I listed the PCM devices with ...
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0answers
32 views

Make zkbd ignore $DISPLAY

Is it possible to make zkbd ignore $DISPLAY variable? I have set up when I log in to different X sessions and it is annoying if suddenly I need to reenter/copy configuration (and I have no idea why ...
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0answers
159 views

(KDE or X ) Script opens konsole in wrong virtual desktop

I have this script. I put it in ~/Desktop. I view the script on my desktop in a "Folder View" widget. When I click on the script, I get list of users, then I get an authorization dialog box ( for a ...
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0answers
496 views

Manually setting environment variables for Metasploit

How do I set manually environment variables for Metasploit, when I execute db_driver I get this message: [*] No Active Driver [*] Available: [*] DB Support: Enable the postgresql driver ...
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votes
0answers
39 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
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0answers
18 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 ...
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0answers
47 views

Counting program fails in arithmetic test

having a little trouble with this rather basic script. This script works on Bash in my macbook pro, but not on my Linux Mint desktop, which also uses bash. I can't figure out what's wrong with it, ...
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24 views

Is there a way to add a timestamp to the logs for qsub job?

I'm submitting jobs on a cluster via qsub but the error/output logs don't have a timestamp, making debugging more difficult. Is there a way to add timestamps to the logs in the bash script? Appreciate ...
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0answers
56 views

How to implement command history in Linux terminal?

I am using Putty as Terminal to connect a Linux server running Oracle Linux. To use a command multiple times, I have to type that command each time. There is no function of Up and Down button unlike ...
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0answers
24 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 ...
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0answers
61 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 ...
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0answers
83 views

Backup And Restore Shell Script

I have been trying to create a script that backups up a certain directory and then restores the directory. The backup works as it should but when I try run the restore function I get the following ...