Questions about bash only, as opposed to other Bourne/POSIX shells. For all Bourne/POSIX-style shells, use the /shell tag instead.

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1answer
31 views

What is the shortest way to select the first available port in a certain range using Bash?

Aim: Select the first available port in a certain range. E.g., if port 600 is unavailable then the availability of port 601 will be checked. Attempt: The following script works as expected but is too ...
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0answers
7 views

PS1 variable inheritance between scripts and programs using bash in AIX

How to ensure that PS1 variable in AIX bash is inherited between cross calling of scripts and programs ? Suppose a program that give to the user a shell instance like the shell command of vi. This is ...
0
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1answer
28 views

What does PROG=${0##*/} mean in a bash script? [duplicate]

PROG=${0##*/} seems to parse out the shell script name, but it's unclear how that works. ${0} I understand is the first or 0th variable.
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2answers
36 views

How do I kill a process after detaching it from bash?

I have multiple scripts that detach a process from bash using nohup and &>/dev/null &. My question is, how do I kill the process after completely detaching it from bash. using killall or ...
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0answers
14 views

Build Script Help, Not Loading Modules

So I am writing a script to build and install Netcdf, but when I source it, it seems like some of the lines just are not running or are being skipped and I am unsure why. When I run the code line by ...
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5answers
88 views

list all files with extension .log except one

I would like to list all files with extension .log except the file backup.log. I have tried using this command: ls *.log -I "backup.log" But all the log files are listed, even backup.log! How ...
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3answers
46 views

Using a function defined in a parent script

I wrote the following script in the test.sh: #!/bin/sh compare() { if [ $1 != root ]; then echo "Fail" >> CAT1.txt fi } awk -F: '$4 == 0' /etc/passwd | cut -d: f1 | xargs -n1 -i bash -c ...
1
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1answer
57 views

Using only in-memory command history

How can I prevent Bash from writing history entries to disk? My ~/.bashrccontains the line trap 'unset HISTFILE; exit' SIGHUP but it doesn't have the desired effect. If I run history -c && ...
1
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1answer
49 views

Write bash_history to a file with a timestamp

I need help with the script below. The requirement is to capture command line history in a file with specific date and time of commands, when they were executed. The below script captures history ...
1
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2answers
123 views

Bash script to read file and echo different lines to output files [duplicate]

I have a log.txt file with various lines of strings and information. I want to write a script to read the log.txt file line by line and any line that contains the word debug I want to put that line ...
0
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1answer
12 views

format of a script which installs programs as root, but configures for a regular user?

I am writing some bash scripts to install and configure some programs. Because the script needs to install packages - I run the scripts as root - which itself is no problem (i.e. I have root ...
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votes
1answer
64 views

how to extract lines between 2 patterns, and save them to different files

hej all, Let' say that we have this file: rrows 35 cols 51 spin 2 %band5 efermi=0.012538 0.004352 0.004317 0.004213 0.004047 0.003828 0.003570 0.003291 0.003011 0.002754 0.002544 0.002408 ...
2
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2answers
63 views

Sort files with a specific extension by modified time and store them into an array

I have found many answers to sort the files of directory and even to save them in an array. Sorting Example ls -t Directory listing in array array=(*) My particular problem needs to sort files ...
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2answers
68 views

Explain the shell command: shift $(($optind - 1))

I am not a Linux guy but stuck in some Script which I have to read for my Project. So can anyone can help me what this command is doing? shift $(($optind - 1))
10
votes
2answers
484 views

Differentiating between running and being sourced in a bash shell script?

Either what I'm asking here is extremely unorthodox/unconventional/risky, or my Google-fu skills just aren't up to snuff... In a bash shell script, is there any easy of way of telling if it is ...
2
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5answers
107 views

Can't login to server with SSH because of a script in /etc/profile.d exiting with exit status 1

so I have this problem, I can't login to my server with SSH. See: ssh -v myuser@myserver debug1: Authentication succeeded (password). debug1: channel 0: new [client-session] debug1: Requesting ...
5
votes
3answers
139 views

Output Output of command to command line directly, NOT variable [duplicate]

I am on the bash shell and I want the output of a command to appear directly in the command prompt that appears after the command has executed ! Example of what I envision it, to illustrate my idea: ...
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votes
1answer
37 views

ls: No such file or directory [on hold]

I have been messing around trying to install macvim to a higher version of 7.4. I finally got it working but now I get the error ls: No such file or directory when looking for a directory. I can ...
1
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2answers
46 views

Exporting a function from .profile/.bashrc

What am I doing wrong...? It's fine if I do this on the command line and then call it but not when I load it from .profile. Linux Mint Qiana, Bash 4.*, if it matters. function android() { command ...
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0answers
28 views

Escape in awk invoked [on hold]

Using this line: sed -i 's/\t*$//' file_a > file_a I would need to incorporate in R in the system command (to execute it in a loop). I know that the escape is / but: system(paste("sed -i ...
5
votes
1answer
102 views

Logging bash output to a file

I'm trying to build vlc which is rather complicated and dependent on having the right packages installed, and keeps choking on errors. To trace all my steps I wish to output what I'm doing to a ...
10
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1answer
270 views

Why Ctrl+m and Ctrl+q wasn't used in bash shortcuts?

Recently I've been viewed through bash shortcuts key, and trying to find an appropriate one for my tmux activate key. And I find an interesting fact that ctrl + m and ctrl + q are not used in bash ...
3
votes
1answer
42 views

Parameter expansion in variable assigned with a wildcard

I have two files in my current folder (MA502) whose names are - MA502_TAAGGCGA-TCGCAGG_L001_R1_001.at.fastq MA502_TAAGGCGA-TCGCAGG_L001_R2_001.at.fastq I have many such folders - ex MA503, MA504 ...
13
votes
3answers
743 views

Can bash write to its own input stream?

Is it possible in an interactive bash shell to enter a command that outputs some text so that it appears at the next command prompt, as if the user had typed in that text at that prompt ? I want to ...
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0answers
21 views

-devilspie doesn't play nice with spawning new terminals

I'm trying to configure devilspie so that on detection of opening a certain directory it runs a script to mount that directory over a network. I don't think the script itself is too important but ...
2
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3answers
42 views

Split command and arguments, and put into variable in a bash script

I have a script that repeats the same (very long) grep command many times. I want to make the script more readable by cutting the line length, so I tried to put parts of the command into variables. ...
0
votes
2answers
55 views

breaking out of command loop but exit code not the reason?

I run the following: echo "while emacs;do echo $?;done;echo Exit code: $?;" | bash If I exit emacs through the menu or the close button, it prints exit code 0 and restarts. If I exit emacs through ...
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1answer
38 views

Matching regular expression with delimited string in unix

Can someone help me in matching the below delimited regular expression in bash script: number|my_name|number I have tried the below but could not get it through end: sed -e 's/[^[[digit]]*//g
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1answer
19 views

Import list of IPs into DEVICE=eth0:X

I have a list of IPs I would like to import into my Linux VPS. They are not an IP range. How would I create a bash script that does this for me? 1.1.1.1 2.2.2.2 If they where my IP lists then it ...
1
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1answer
44 views

Display a line in a text file if variable matches a part in the line?

I'm making a stock checker. I have a file with all of the NYSE exchanges and their descriptions. The descriptions start on the first tab enter of the file. The file formatting looks like this: A ...
2
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1answer
31 views

View remote value of $PATH inside shell script

When executing this bash script, it only shows my local path. ssh ${REMOTE_HOST} 'bash -s' <<EOL set -e source ~/.profile echo $PATH # Commands here don't work because $PATH is ...
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2answers
65 views

Bash script with data from another file

I have worked on the following script which I want to use to easily add multiple Postfix as well as a few other things. Below is a small sample postmulti -e init postmulti -I postfix-$new -e create ...
0
votes
1answer
34 views

How to escape an input string in Bash [closed]

I'm using the jq tool to handle some JSON in bash. Just one problem, while using this line: PB_ACL="acl="`echo $IMGREQ | jq -r'.data.acl'` Result: echo $PB_ACL // acl= The expected value jq ...
1
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1answer
38 views

Find last line of a file for matching string?

I want a loop that runs infinitely over a file but always checks the last line to see if it contains the matching string if it does then echo that line and keep the loop running. What I have right now ...
4
votes
1answer
71 views

Is there a command line tool to manage unix signals?

Is there a command runner like env, nice, nohup, etc., that can run a program with modified signals? In my case, I need something to reset SIGINT to SIG_DFL. Why do I need this? Because ...
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2answers
22 views

Saving a piped value went wrong

I installed jq to handle some JSON with bash. But somehow piping the JSON string to jq in combination with saving it's output to another variable went wrong. TEST='{"foo": "bar"}' PB_SIG=$TEST | jq ...
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0answers
14 views

How to get back my splitted screen after I lost connection

I was executing the screen command with a splitted window in my CentOS server then I lost connection to it. I reconnected to my server and I did screen -r to get my screen back but now I don't see ...
5
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2answers
283 views

Why does `cat` seem to iterate over JSON arrays?

I'm puzzled by this behaviour of cat when trying to output a heredoc containing JSON in bash 3.2: input: $ cat <(cat <<EOF > {"x":[{"a":1,"b":2}]} > EOF) output: {"x":["a":1]} ...
10
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3answers
796 views

How to understand “cat > file_name << blah” command?

In following command cat takes the content of here-doc and redirects it to file named conf: cat > conf << EOF var1="cat" var2="dog" var3="hamster" EOF How to understand the order of ...
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2answers
46 views

viewing printf after pipe (or subshell?)

Ok, this is hard to distill to a single question because it really depends on how I'm going to troubleshoot it. The following script is meant to pipe mount.cifs commands to a while loop that enters ...
0
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1answer
32 views

Python output in XML format

I have a python script which compare IP list with IP Database and gives output of matching criteria. (I got the script from this forum). convert.py #!/usr/bin/python import socket,struct ...
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2answers
29 views

How do I generate diffs for a series of files?

I have a series of a few thousand files, all with filenames in order, so let's say file1.x, file2.x, file3.x, etc. All these files are in the same directory. I know how to generate a diff from ...
2
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1answer
117 views

g++ bash: warning: programmable_completion: g++: possible retry loop

When I type g++ and do tab completion for file listing, I get this warning **g++ bash: warning: programmable_completion: g++: possible retry loop** I googled it and so far no results . Can ...
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2answers
57 views

bash scripting and PS1 prompt

Im trying to customize the way the PS1 prompt shows in terminal and CLI on Arch Linux, but it's not printing the proper thing it should be doing. First up is I'm trying to colorize parts of the PS1 ...
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2answers
59 views

command substitution: /dev/stdin: Permission denied

Want to read whole stdin into variable. Don't want to spawn new processes. From bash manual: The command substitution $(cat file) can be replaced by the equivalent but faster $(< file). It ...
0
votes
1answer
42 views

Binary not accesible from Bash despite being in path

I am learning how to program in Racket. It's binary is in "/Applications/Racket v6.2/bin/racket". Let me show what happens: MacBook:~ enedil$ echo $PATH /Applications/Racket\ ...
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votes
1answer
28 views

How to kill only current process and continue with shell pipe-line?

I have 2 related Doubts about Bash. (Q1) Consider tail -f SomeFile | wc, a fictitious command-line, where tail is used to simulate a command (C1) which runs for a long time, with some output from ...
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3answers
94 views

How to kill this process in bash

I am trying to interface my homemade Raspberry Pi-powered arcade machine with a coin acceptor, and for that I: use a shell script (named gameplay) which starts the game emulator (MAME) when a coin ...
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votes
1answer
39 views

Execute bash snippets directly in shell? [closed]

Is there any way to execute small bash snippets in the shell? If you don't want to edit a file again and again and test it by executing it again and again (in fact by jumping forth and back between ...
1
vote
2answers
27 views

bash command/script to reset default route

I manage several OpenWrt (embedded linux) routers for which I've written bash scripts to run an Openconnect VPN client. The client uses "vpnc-script" to set up routing, which replaces the initial ...