Questions specific to GNU’s Bourne Again SHell, as opposed to other Bourne/POSIX shells. For questions about Unix shells in general, use the /shell tag instead.

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0
votes
1answer
763 views

How do I put a checksum in a script?

I was (am) having trouble installing Eagle on my Linux (debian 8 jessie) computer. I was reading the installer script, when i noticed there is a checksum for the install script in the install script? ...
0
votes
2answers
110 views

Whats wrong with this case statement?

UPDATED: I am trying to do some color changes with my keyboard using apexctl depending on what time it is. But my case statement is giving me trouble. I want to compare the time when the script runs, ...
0
votes
0answers
241 views

Dynamically Source Bash & Profile Files Across Multiple Enviornments

I'd like to come up with a way to always source the user's profile and bash configuration files upon a interactive login or non-interactive login despite what file structure they may have. It would ...
2
votes
2answers
759 views

Separate filename and path inside find command's -exec option

I'm struggling with escaping and expression evaluation. I am trying to run a command inside a find...-exec COMMAND structure, where COMMAND operates on one file and outputs to the stdout. To use ...
1
vote
2answers
890 views

Get files from SFTP server and manipulate in memory

Is there a BASH way that is able to access a SFTP server, "access" a file and without downloading it read it in a buffer, manipulate the content and then store it locally. I know this can be done ...
4
votes
3answers
2k views

How to pass the content of a file as multiple arguments in bash

I have a file that contains data that gets updated over time (mydata). The file looks like this: 1 2 3 With this file, I want to do this (basically handle each number as a separate parameter): ...
60
votes
2answers
9k views

Why does bash think: 016 + 1 = 15?

Can somebody explain to me why a number with a leading 0 gives this funny behaviour? #!/bin/bash NUM=016 SUM=$((NUM + 1)) echo "$NUM + 1 = $SUM" Will print: 016 + 1 = 15
4
votes
4answers
1k views

Flattening folder structure

I have this folder structure: ├── foo1 │   ├── bar1.txt │   └── bar2.txt ├── foo2 │   ├── bar3.txt │   └── bar4 with a space.txt └── foo3 └── qux1 ├── bar5.txt └── bar6.txt that ...
0
votes
1answer
570 views

Adding timestamp into log file via cronjob command [duplicate]

I try to run git pull command with loging output message to file every 5 minutes. But i got error like this, (root) CMD (cd /var/www/sites/ && git pull origin master | sed -e "s/^/$(date +\")...
4
votes
1answer
213 views

bash [[ = ]] behaviour

man bash: [[ expression ]] [...] Expressions are composed of the primaries described below under CONDITIONAL EXPRESSIONS. Word splitting and pathname expansion are not performed on the words ...
7
votes
5answers
2k views

Store 2^500 in a variable in bash

I want to store the value of 2^500 in the variable DELTA. I'm doing export DELTA=$(echo "scale=2; 2^500" | bc) but this does not set DELTA to ...
1
vote
3answers
644 views

Variable expansion in Bash

I tried the following commands variable='one|name' echo $variable The output is one|name whereas echo one|name gives an error No command 'name' found. This is reasonable because bash treats | as ...
0
votes
1answer
118 views

I am accessing remote machine in linux using Bash scripting

I am accessing a remote machine using the ssh command and a pem file. My code is as follows: #!/bin/bash ssh -i rijo.pem ubuntu@90.45.74.51 <<EOF sudo -s var=`cat /opt/revsw-config/varnish/...
6
votes
2answers
2k views

What does `date 2&>$0` do?

I am looking at a co-workers shell code and I saw this: date 2&>$0 I know what date does, but what's 2&>$0 doing? He's out for a while, so I can't ask him what this part was about.
4
votes
2answers
5k views

parse one field from an JSON array into bash array

I have a JSON output that contains a list of objects stored in a variable. (I may not be phrasing that right) [ { "item1": "value1", "item2": "value2", "sub items": [ { "...
1
vote
2answers
89 views

Modifying part of a string in bash script

I have a file named variables.f90 , having many lines defining different variables, as follows :: integer::n_monomer=6800 real*8::rx=5.0d0 #... randomly integer and real numbers defined real*8::...
16
votes
6answers
5k views

Drawing an histogram from a bash command output

I have the following output: 2015/1/7 8 2015/1/8 49 2015/1/9 40 2015/1/10 337 2015/1/11 11 2015/1/12 3 2015/1/13 9 2015/1/14 102 2015/1/15 62 2015/1/16 10 2015/1/17 30 2015/1/...
2
votes
5answers
5k views

Bash rename 360 000 files using find -exec

I've got around 360 000 files like: ./001/1/1.jpg ./001/1/2.jpg ./001/2/1.jpg ./002/1/1.jpg ./003/1/1.jpg ... pattern: [60 dirs]/[1000 subdirs]/[4-10 files].jpg I want to rename files using rename ...
1
vote
1answer
77 views

Killing bash causes it to respawn itself

I'm SSHed into my computer at home and I'm trying to format a drive. lsof /dev/sdb2 shows: COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME bash 1366 mitch cwd DIR 8,18 24576 ...
2
votes
1answer
942 views

awk in ssh in su in a command substitution

I am creating a script that will ssh to a host and print all the user accounts and when they will expire. On a host I can run awk -F':' '{ print $1}' /etc/passwd and it will give me a list of all ...
0
votes
1answer
262 views

create a user via script

I want to create a new user in a specific group when I issue the below command. sudo ./create_user.sh "test" "firstname lastname" The create_user.sh script looks as below. #!bin/bash #sudo ...
0
votes
0answers
28 views

Broken mkdir command [duplicate]

I made an alias in my .bash_profile file with the same name as mkdir. It looked like this. alias mkdir='function _blah(){ mkdir "$1"; cd "$1" };_blah' After removing it, i notice that mkdir still ...
0
votes
1answer
227 views

Can't concat file paths, permission denied

I can't realize why if I just try to concat some file paths (without opening the files), I get "permission denied": #!/bin/bash if [ "$#" -eq 1 ]; then path1= "./src/$1" path2= "./...
0
votes
1answer
922 views

Redirecting Standard Output And Standard Error to One File [duplicate]

I have come to understand that we have two methods of redirecting both stdout and stderr to the same file. The first method is: ls -l /bin > ls-output.txt 2>&1 As the author of this book ...
1
vote
0answers
46 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 ...
1
vote
3answers
298 views

iterate over file and send lines as positional parameters to another file

I would like to iterate through a file containing dates (named dates.txt) in the following format: 2009 08 03 08 09 2009 08 03 09 10 2009 08 03 10 11 2009 08 03 11 12 2009 08 03 12 13 2009 08 03 13 ...
2
votes
1answer
64 views

Is there a way to copy a rectangular area in a bash or konsole terminal?

Is there a way to copy a rectangular area in a bash or konsole terminal? Is something like this supported on the normal terminal, or will it be only available on terminals run in a GUI environment?
0
votes
3answers
2k views

VLC script on ubuntu server

I need a small script which run three vlc command on the same time (on Ubuntu server 14.04) as stated below: #!/bin/sh cvlc -vvv v1 --sout "#transcode{vcodec=h264,vb=999,acodec=mp3,ab=128,...
0
votes
0answers
311 views

restrict ssh access to /bin and using bash as a shell

I want to restrict my admin user to /bin directory while permitting to use bash as a shell via ssh. This is in my sshd_config file: Match User admin ChrootDirectory /bin X11Forwarding no ...
1
vote
1answer
107 views

How to trim the CWD, shown in the command promt

To know, what is my CWD in console, I added the following to ~/.bash_profile: export PS1='$(pwd)$ ' So, pwd result it shown before the $ symbol. It was very nice. But when I go to a directory with ...
2
votes
2answers
3k views

output both stderr and stdout on console and store them in a file at same time

may I output both stdout and stderr on console screen and store one of them into a log file? I write a test shell script: #!/bin/sh echo OUT! >&1 echo ERR! >&2 I can output both of ...
2
votes
1answer
510 views

How can I list hidden directories, then directories, then hidden files and finally files with ls?

I'm trying to figure out how to list the contents of a directory in the following group order: Hidden directories Non-hidden directories All other hidden files (including regular files, symlinks, ...
2
votes
1answer
235 views

Behaviour of 1>&0 in bash

So I am trying to learn more about file descriptors and their redirections. At the moment I am exploring an edge case of doing 1>&0 and I cannot quite understand what is happening there. $ ...
0
votes
1answer
137 views

Selectively record commands and output from terminal to MySQL table

In some situations I would like to store complete commands and output from terminal sessions in a MySQL database. Ideally I would just copy the command and output from the terminal to my clipboard ...
3
votes
3answers
3k views

Need to insert single quotes in text file for use as SQL query using sed

I have created a line of text that looks like this: INSERT INTO radcheck(id, username, attribute, op, value) VALUES (,,00:23:32:c2:a9:e8,Auth-Type,:=,Accept); I want to use sed to make it look like ...
0
votes
1answer
101 views

How do I write a bash script to report machine states and conditionally ping them? [closed]

#!/usr/bin/bash array1=( HPUX2 HPUX3 ) array2=( `cat $HOME/testo |awk '{print $2}'` ) The file testo,report HPUX2 OFF HPUX3 ON I want my script to report "Machine HPUX2 is OFF" and machine ...
3
votes
4answers
10k views

How do I test if an item is in a bash array?

Help for a simple script #!/bin/bash array1=( prova1 prova2 slack64 ) a="slack64" b="ab" if [ $a = $b ] then echo "$a = $b : a is equal to b" else echo "$a = $b: a is not equal to b" ...
0
votes
0answers
30 views

Pipe to `ls` Not Working as Expected [duplicate]

When I issue: [dave@dhost ~]$ which tar | ls -l I get the output of ls -l of the pwd. I expected to get: -rwxr-xr-x. 1 root root 395472 Feb 21 2013 /bin/tar Why doesn't the pipe work as I ...
13
votes
2answers
47k views

sudo as another user with their environment

$ whoami admin $ sudo -S -u otheruser whoami otheruser $ sudo -S -u otheruser /bin/bash -l -c 'echo $HOME' /home/admin Why isn't $HOME being set to /home/otheruser even though bash is invoked as a ...
2
votes
0answers
230 views

Bash Executing Script from within Script Causes Echo and Read Issues [closed]

I appear to be having unexplainable issues with scripts run from within a subscript. I've been unable to acquire a solution so I will give you what I can to help me solve it. Problem: when a script ...
0
votes
1answer
175 views

For loop brackets - C like syntax

When i am using the below syntax to iterate why two brackets are needed ? for (( expr1; expr2; expr3 )) do command1 command2 .. done and the below code doesn't work ? and throws error "syntax ...
0
votes
1answer
258 views

bash shell - how to do nested loop without “syntax error: operand expected” [duplicate]

I am trying for i in {4..100} do is_prime=true a=$(($i-1)) for divider in {2..$a} do b=$(($i % $divider)) # <-- line 9 [ $b -eq 0 ] && echo 'y' #is_prime=false done [ ...
5
votes
3answers
1k views

Using | pipe character from a $variable makes it treat as just another argument in bash; how to escape it?

I have a bash script like this export pipedargument="| sort -n" ls $pipedargument But it gives the error ls: |: No such file or directory ls: sort: No such file or directory It seems to be ...
2
votes
0answers
401 views

Unable to create a configuration directory for [FishShell] Please set the $XDG_CONFIG_HOME variable

I'm getting this error when starting fishshell: melanie:~ melanie$ fish fish: Unable to create a configuration directory for fish. Your personal settings will not be saved. Please set the $...
0
votes
1answer
226 views

From Mysql query output to retrieve files in the file system and rename the files

I have to call a SQL query from bash that outputs 1000 rows of two columns File_Path (Eg., /opt/files/dest/2.bin) Name_of_the_file (Eg., fax attachment.pdf, invoice.docx... yes, there are spaces). ...
3
votes
2answers
428 views

closing parent process(terminal) doesn't close a specific child process

I'm new to Linux and so far,I have come to understand that if we open a new process through a gnome-terminal eg: gedit & "& for running it in background", then if we close the terminal, gedit ...
7
votes
2answers
519 views

Shell script not able to awk created file

I'm trying to create some simple pass/fail test scripts, but I am having some challenges as outlined below. My intent is to get the full results of a command (such as ping) into a results.txt file to ...
0
votes
2answers
291 views

Combining two bash script and using a menu

I have two scripts, one that is used on a folder with csv files and another on a folder with .tar.gz files. In the second script, I first unzip the files before doing anything with them. Now I want to ...
3
votes
1answer
260 views

What is the difference between letting nohup append to 'nohup.out' and explicitly redirecting it to a file?

Consider the following scenario: tail.sh: #!/bin/bash tail -f test.txt invoke.sh: #!/bin/bash nohup ./tail.sh & invoke_explicitredirect.sh: #!/bin/bash nohup ./tail.sh > out.log & ...
1
vote
1answer
211 views

Echo newline with quotes [duplicate]

For: $hello="hello > world" Why does echo not print the newline for: echo -e $hello But if I put $hello in quotes it does. $ echo "$hello" hello world Is this because of ANSI-C Quoting? ...