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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0
votes
2answers
43 views

Echo a string with a variable in it without expanding/evaluating it [closed]

I've searched everywhere. Tried echo and print. Tried single and double quotes. But I have parsed data and assigned it to a variable and would like to then evaluate it for if there is a variable ...
1
vote
0answers
20 views

Bash tab completion not working within symlinked directory

I'm working with Bash 4.2.46 on RHEL7 with the bash-completion packages installed, but I seem to have found an odd corner case where tab completion doesn't seem to work as expected. I have a set of ...
-1
votes
0answers
27 views

dump non formated output of commands to csv file

I have some commands with which i can get list of VMs running on hypervisors. I redirect that output to some file.txt and use while loop to read each line from file.txt and execute two more commands ...
1
vote
2answers
43 views

How to define alias for non interactive/non login shell?

I have a user (zabbix) with shell set to /sbin/nologin. The user's home is /var/lib/zabbix and I inserted alias curl='curl -k' into ~zabbix/.bashrc. However it does not work when I (for testing ...
13
votes
6answers
395 views

Use system command instead of Bash builtin without specifying the full path

I use Bash as my interactive shell and I was wondering if there was an easy way to get Bash to run a system command instead of a shell builtin command in the case where they both share the same name. ...
1
vote
1answer
156 views

How to change a pom.xml version with linux shell script

i have a pom.xml contain a line <version>x.y.z-tag</version> where tag could be: snapshot, alpha, beta or release. and x.y.z is a number version like: 1.0.0 or 1.2.1 .... i want to ...
1
vote
1answer
40 views

if condition in bash scripting

I have a text file that I want to check some line as below com1=`awk 'NF{a=b;b=$0} END{print (b ~ /\com/)? "Yes" : "No"}' $myfile` com2=`awk 'NF{a=b;b=$0} END{print (b ~ /\t/)? "Yes" : ...
2
votes
2answers
352 views

Cannot rm file: Disk quota exceeded

In bash (and over ssh) running rm FILENAME gives the error: rm: cannot remove 'FILENAME': Disk quota exceeded. I've seen the other posts (and everyting down the first page of google) on this topic and ...
1
vote
2answers
38 views

Recover from faking /proc/meminfo

So, without really thinking too much, I ran this script: #!/bin/bash SWAP="${1:-512}" NEW="$[SWAP*1024]"; TEMP="${NEW//?/ }"; OLD="${TEMP:1}0" sed "/^Swap\(Total\|Free\):/s,$OLD,$NEW," /proc/meminfo ...
0
votes
0answers
34 views

Does RPM automatically retry failed download attempts?

My particular situation isn't on a Linux box, rather an IBM i. But I'm running RPM within a BASH shell and attempted to download and install nano using RPM - it failed. I didn't think anything of ...
-1
votes
1answer
37 views

Replace duplicate rows by one column [duplicate]

I have a file in the below format. [ I tried using awk and sed in all the possible ways which i am aware of but couldn't find a way to reformat the file in the format which i am looking for. I would ...
2
votes
2answers
909 views

Any way in Bash to write to a file every X seconds without closing it?

The hardware watchdog on my system needs a 0 written to /dev/watchdog at less than 60 seconds interval or it will fire. The file handle must be kept open however or the watchdog is then disabled. ...
0
votes
1answer
19 views

get command line agrument by variable in shell script

I want to get the arg of a command from a var that has the index in it of the arg that I want. Something like this # command in terminal, `foo -r -f value_wanted` index="3" var=$"$index" echo $var ...
3
votes
2answers
982 views

How to count occurrences of all the words in all the files of a directory using grep? But with count incremented only once per word per file

I have already asked a similar question but people misunderstood what i was asking. I was asking how to generate a list of every word with a word count incremented only once per word per file. For ...
0
votes
3answers
50 views

piping with grep

I want to search "C" in the grades column inside the file "input.csv": roll,name,total,rank,grade 001,A B,78,23,C 003,F YZ,100,1,* and what I'm trying is: cut -d"," -f4 input.csv | grep "C" ...
4
votes
1answer
67 views

Why is subshell created by background control operator (&) not displayed under pstree

I understand that when I run exit it terminates my current shell because exit command run in the same shell. I also understand that when I run exit & then original shell will not terminate because ...
27
votes
5answers
65k views

How to measure time of program execution and store that inside a variable

In order to find out how long certain operations within a Bash (v4+) script take, I would like to parse the output from the time command "separately" and (ultimately) capture it within a Bash variable ...
0
votes
0answers
41 views

Pg_dump does not work in Cron

I have the command below and run it succesfully: /usr/lib/postgresql/9.1/bin/pg_dump -U dspace --format=c --file=/dspacebkp/dspace_db_$(/bin/date +\%m\%d\%Y)_uncompressed dspace I can see my new ...
3
votes
2answers
64 views

How does the -d option to bash read work?

I have a bash script where I'm trying to assign a heredoc string to a variable using read, and it only works if I use read with the -d '' option, i.e. read -d '' <variable> script block ...
0
votes
0answers
15 views

How to edit $PATH? [duplicate]

After searching, I can't still figure out how to edit $PATH. Now its value is: ...
0
votes
1answer
16 views

bash: /home/hadoopuser/hadoop/sbin: Is a directory

I am in Ubuntu 14.04 LTS. Based on how to set a Hadoop cluster I am executing this: # Add Hadoop bin and sbin directory to PATH export PATH=$PATH:$HADOOP_HOME/bin;$HADOOP_HOME/sbin where I know ...
2
votes
1answer
33 views

Automatically add slash when navigating through symlink

I use symlinks a lot and pretty much linked my whole home directory into a folder .other or .dotfiles. When I'm im my home directory and try to got into the folder .config/, its actually a symbolic ...
2
votes
4answers
52 views

Change dir from script without a “shell procedure” or “sourcing the script”

I know what I can make a shell procedure or source the script instead of running it to cd the shell I am using. What I want to know is there any way to cd the "parent shell" (not sure if that is the ...
0
votes
0answers
18 views

lftp — continue behavior?

I have a straight forward use case that I thougth lftp could do with the --continue flag - alas it didnt work. Is it doable? - Am I missing some flags, and are there any easier way to do this with ...
1
vote
3answers
31 views

Print array line by line in a here doc

I currently have the following here doc message=`cat <<-EOF Test data: Test data 1: "${Test_data_array[@]}" EOF` echo "$message" Is there a way to get the array to display multi-line per ...
6
votes
1answer
10k views

How to recover a backgrounded job from a previous shell? [duplicate]

Possible Duplicate: How can I disown a running process and associate it to a new screen shell? I launched a command that lasts a long time. I had to disconnect so I moved it in the ...
1
vote
1answer
43 views

SIGINT handling differences between bash 3 and 4

I have a script which works great in bash 4.3, but gives me unexpected behavior with bash 3.2. Here's a simplified version: set -o errexit -o pipefail task() { local name=${1} local ...
3
votes
2answers
64 views

What does “if echo $line | grep -F = &>/dev/null” do?

I'm not sure what the following line does in a bash script: if echo $line | grep -F = &>/dev/null then ... I know &>/dev/null is short for >/dev/null 2>&1, I'm not sure, ...
19
votes
9answers
19k views

Is there a way to make “mv” fail silently?

A command like mv foo* ~/bar/ produces this message in stderr if there are no files matching foo*. mv: cannot stat `foo*': No such file or directory However, in the script I'm working on that case ...
1
vote
2answers
69 views

BASH how to save output of rm with timestamp?

I nearly have this working, This is a script that will run in CRON to keep the latest 10 backups, and remove anything else, I want to log this to keep track to make sure all is in good order, I have ...
19
votes
3answers
883 views

Why does bashrc check whether the current shell is interactive?

On my Arch install, /etc/bash.bashrc and /etc/skel/.bashrc contain these lines: # If not running interactively, don't do anything [[ $- != *i* ]] && return On Debian, /etc/bash.bashrc has: ...
2
votes
2answers
40 views

Autocomplete from grep output

How might I more easily use a filename found by grep as an argument to vim: $ grep -r foo * lib/beatles/john.c lib/pantera/phil.c lib/pinkfloyd/roger.c lib/pinkfloyd/richard.c ...
40
votes
3answers
5k views

How does `yes` write to file so quickly?

Let me give an example: $ timeout 1 yes "GNU" > file1 $ wc -l file1 11504640 file1 $ for ((sec0=`date +%S`;sec<=$(($sec0+5));sec=`date +%S`)); do echo "GNU" >> file2; done $ wc -l ...
0
votes
3answers
75 views

Using bash variable substitution instead of cut/awk

Can I use bash variable substitution to extract a piece of a variable based on a delimeter? I'm trying to get the immediate directory name of a filename (in this case, foo). $ ...
13
votes
2answers
46k views

Changing a file's “Date Created” and “Last Modified” attributes to another file's

I'm using merge cap to create a merge pcap file from 15 files. For the merged file, I have changed the name to that of the first of the 15 files. But I would also like to change the merged file's ...
3
votes
1answer
57 views

Is it possible to save the output of a previous command on file?

Quite often, I'm in the following situation: I launch a command on bash (that takes lot of time to be processes) and I get a long output, which doesn't fit into the terminal and it can't be read ...
1
vote
3answers
43 views

bash multi-threads help require

I have a list of IPs and I need to check them for opened ports using nmap. So far, my script is like this: #!/bin/bash filename="$1" port="$2" echo "STARTING NMAP" while IFS= read -r line do nmap ...
0
votes
2answers
37 views

Input redirection using command and options

I am trying to write a script that takes in 2 parameters - program name and optional flags. I am trying to execute the program command on an input_file and store the output in the output_file. ...
0
votes
1answer
2k views

Changing title without changing prompt on Cygwin

I have the following shell script function from this site that allows me to change the title in both Putty and Cygwin. In Putty connected to a Linux host it changes the title and leaves the prompt as ...
4
votes
4answers
30k views

Yum update problems on CentOS 6.5 minimal as VMware guest

INFO: I am using Windows 7 Pro (64bit) with VMware Workstation version 10.0.1 . I am using CentOS(64bit) 6.5 minimal, for the first time. I am running this from my workplace network, which may use a ...
12
votes
5answers
3k views

Abbreviated current directory in shell prompt?

vim has a really nice feature which it utilizes in its paths when they're a bit long: It abbreviates the path to the document in the tab at the top. Is there a way to do something similar to this ...
3
votes
4answers
68 views

Sticky entries in shell history

Is there a way one could make some commands "sticky" in a shell history? I want to save some favourite commands that would be searchable with Ctrl+R, like the rest of the history, but they should ...
5
votes
2answers
41 views

How to store a path built with wildcards and containing with spaces into a variable

Here's the situation (I'm on a Mac, OS X El Capitan): # This works: $ cd /Applications/Adobe\ Illustrator*/Cool\ Extras.localized/en_US/Templates/; # These do not work: $ ...
7
votes
1answer
67 views

How to get the GPU execution time of a script in the shell?

I would like to display the completion time of a script, in terms of GPU time (not CPU). For the CPU, I can simply use time: francky@gimmek80s:~$ time ls -l total 8 drwxrwxr-x 3 francky francky 4096 ...
2
votes
3answers
65 views

log out via shell script

I am doing some operation via shell script. If that script is successful, continue else logout of the current user. I am unable to find a way to logout of current user. I tried to use exit but seems ...
2
votes
1answer
23 views

Repeat based off user input OS X

I am creating a script which asks a user to enter a message then how many times they would like to display that message. This is what I have so far. message.sh #!/bin/bash echo -en "Enter a ...
4
votes
2answers
193 views

How to completely detach a process

I want to spawn a process and run it at the top level so that when the shell exits, the process keeps running. I had mistakenly thought that nohup would do this, but when I exit from the shell (the ...
5
votes
1answer
1k views

A script's background process is still alive after closing the terminal

This is more of a process management/signal handling question than a Bash question. It just uses Bash to explain the issue. I'm running a Bash script in which I run a background process. This is the ...
6
votes
1answer
102 views

Is it possible to add a process to the job list in bash (e.g. to reverse “disown”)?

If I disown a job in bash and change my mind, can I undo it somehow ? If so, taking it further, is it possible to bring an arbitrary process under job control (an acceptable restriction would be that ...
0
votes
1answer
25 views

problem in login with default /bin/fish shell in gdm

I set my user default shell to fish. /etc/passwd file: mlibre:x:1000:1000::/home/mlibre:/bin/fish and then, in GDM I can't login with my user (mlibre). GDM prints some error. Then, I changed back ...