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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Is it possible I can look at the source code of the patches that fixed the Shellshock bash vulnerability?

I have a project for my grad level OS class, and I have decided to choose the Shellshock vulnerability bugs as my topic. There is a lot of great information out there, but I was curious if it is ...
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3answers
20 views

Renaming multiple Files, Bash Script, preferably with an Addition

Hello you wonderful people, I have a little problem creating a Bash Script. I have 7000 image files (dicoms). These files belong together and should be in order in ONE directory. However, the program ...
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3answers
30 views

How to use password in shell scripting

I am writing a script which greps for for multiple files from 3 log files. One of the log file is created as superuser and every time it executes it prompts for password. How do I put it the same ...
3
votes
4answers
221 views

Is it possible to reverse a command in the bash shell?

I was wondering if there is a (simple) possibility to redo/reverse a command that was executed in the bash shell? (to make it undone) Is there something similar to the ctrl+z combination to redo any ...
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0answers
22 views

delete non important characters from command output

the version command in my Linux machines display the following output version Red.Hat.OS. release..........5.5 APP.Release.............4.2.0.0-02 how to remove the middle "." dot character ...
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0answers
17 views

Why the output is not written to log from expect shell script

I am trying to write the output of the netcat command including the command also to a file by logging into remote servers. But it is not writing. What am i missing ? #!/usr/bin/expect -f set user ...
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0answers
20 views

bash command to simply print new bash commandline like [tom@cerulean ~]$ [on hold]

My shell script used carriage return '\r' to erase my current [tom@cerulean ~]$ bash line to print an information (that is run asynchronously then returned when done). I want something that will to ...
0
votes
1answer
19 views

cron: output of a script?

I've got a cronjob that looks like this 0 0 * * 7 [ $(date +\%d) -le 07 ] && /home/archiver/archiver.sh &> /home/archiver/output And it works from the cron+bash perspective in that ...
1
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1answer
37 views

When did bash quit exporting SHELL?

I upgraded a Debian box from stable to Jessie and I noticed that SHELL is no longer exported, so screen and similar programs start dash for subshells instead of bash. When was this change made and ...
2
votes
2answers
45 views

How do I swap the two last command line arguments?

$ ln -s ./dir/target.txt /path/to/source.txt{cursor here} How do swap file typed filenames in command line? Alt+T swaps words, not filenames, resulting in ln -s ./dir/target.txt /path/to/txt.source. ...
7
votes
4answers
500 views

Spaces next to pipes

I've seen history | grep blah and history |grep blah; and history|grep blah also works, though no one ever seems to use it. Is there any significance in the spaces (e.g. piping to/from different ...
0
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2answers
22 views

use backquotes in a script [on hold]

Why this difference between echo $Date and echo "$(date +%s_%kh%M_le_%a_%d_%b_%Y)"? beginning=$(date +%s) diff="0" rest="$1" tmp="0" now="0" Date=`date +%s_%kh%M_le_%a_%d_%b_%Y` echo -n "$1" while [ ...
0
votes
2answers
32 views

Gzip file but excluding some directories|files and also append current date

I'm looking for a way to create a .tar.gz file from a directory but I have some doubts. I'm know that the command for create the file is: tar -zcvf /path/to/compressed/file.tar.gz /path/to/compress ...
3
votes
1answer
51 views

How to swap two commands in bash?

Say I have command A and command B but I want B to run when I type A and vice versa. I've tried alias A='B' alias B='A' But this doesn't seem to work for some reason. How do I do this? EDIT: ...
3
votes
1answer
24 views

How to sort an associative array and retain the keys?

I have an array with filenames as keys and a numerical value as values. MYARRAY[00001.jpg] = 31 MYARRAY[00002.jpg] = 200 MYARRAY[00003.jpg] = 98 I need to sort them so they are ordered by value. ...
1
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0answers
37 views

Bash cannot see PATH update

I am running Debian on a VM. I login to the GUI and go to Applications > Accessories > Terminal. # echo shell: /bin/bash I modified ENV_SUPATH, ENV_PATH inside of /etc/login.defs. I restarted ...
1
vote
2answers
21 views

Does X mangle prompt environment variables?

I'm starting it with startx. Before that I have PS1 in my environment: $ cat /proc/self/environ | tr '\0' '\n' | egrep '^PS' PS1=[\u@\H \w] PS3=> PS2=> PS4=+ From inside X I get: $ cat ...
1
vote
1answer
21 views

Why did a recent Ubuntu 14.04 update mess up my PS1 prompt?

I recently updated my Ubuntu 14.04 using the software update. This caused some problems. Initially I couldn't open up a new terminal window due to unknown errors with my .bashrc I had to use ...
0
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2answers
24 views

When is /etc/bash.bashrc invoked?

What is this file anyway? Documentation makes no mention of it. And it's not supposed to be run automatically (version 4.3, 2 February 2014): Invoked as an interactive login shell, or with --login ...
3
votes
1answer
38 views

How to append MD5 checksum of email content in bash?

I found some lines of output missing from an auto-generated email notification that was dispatched via cron. Having confirmed that there is no AVC error, I want to find out if the integrity of my ...
3
votes
3answers
74 views

spawn - command not found!

I am using Mac OS X 10.9.4, following is my script to copy files from local machine to different host #!/bin/bash #!/usr/bin/expect echo "I will fail if you give junk values!!" echo " " echo "Enter ...
2
votes
1answer
45 views

Test if postfix is running

I'm searching for a reliable way to test if postfix is running from inside a bash script. My first attempt was simply trying pidof postfix, which doesn't work. Then I tried to get the postfix ...
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0answers
3 views

Generating a .img from tarball: The /dev/loop devices

I'm trying to make a .img from a tarball using the following script: #!/bin/bash # Packages required # dosfstools parted # Can be run on any Linux system # loop.max_part=15 must be in kernel ...
1
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1answer
78 views

Swap two files in bash [duplicate]

How do I swap two files in Linux console with minimum typing? Boring approach: $ mv file1.dat fileX.dat $ mv file2.dat file1.dat $ mv fileX.dat file2.dat
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votes
2answers
59 views

Use lines in a file to produce string and file name

I have a file, foo.txt, that has a folder name on each line: folder_1 folder_2 folder_3 And I'd like to do something like this: cat foo.txt | xargs -I {} echo 'function {}() { return stuff; }' ...
0
votes
1answer
32 views

How does `ls` know whether it's piped or printed [duplicate]

ls normally prints like this: 1 1249 1653 23 33 4581 6202 6447 789 836 903 config.gz kpageflags sysrq-trigger 10 1253 1658 24 34 4582 6206 648 79 837 ...
0
votes
1answer
36 views

Why does the input to xargs is 1 string but without is strings in separate line?

I am trying to pipe file to rm via xargs. I understand that what I am tryng to do could be done by git clean but I am practicing the cli. I tried this: for files in $(git status --porcelain| sed ...
0
votes
1answer
15 views

Values from two lists are not processing correctly within two nested loops

I am trying to pass some values contained in two lists to a simple echo within two nested for loops (the echo is used to look at what is generated inside the inner loop). But the results are not ...
1
vote
3answers
39 views

How do I use inserted values using getopts

I have this bash code combined with getopts and if I understood getopts correctly OPTIND contains the index of the next command line option and all the command line options provided to shell script ...
-1
votes
1answer
24 views

using the sed command in bash show output in a new text file? [on hold]

Hey everyone I am new to the world of UNIX/Linux.My professor wants my class to use sed command to display output in a new text file but did not give us the commands; any help would be useful thanks
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0answers
16 views

Using a custom script for cron jobs mail notification

After coming across Mailgun I would like to write my own script to use their API in order to send mail notifications from cron jobs — avoiding in this manner having to worry about installing a ...
1
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3answers
48 views

Traverse all subdirectories in and do something in Unix shell script

I am new to bash scripting. I am working on a shell script and got stuck from last 3 days. I want my shell script to visit all subdirectories in a main directory. Do something in directories, sent ...
0
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0answers
28 views

Unrecoginzed option: using 'getopt' cmd in shell script [on hold]

What is wrong in the command: if ! options=$(getopt -n myscript -l a:,b:,cc:,dd:,ee:,ff:,gg:,hh: -- "$@"); then exit 1; fi I get an error msg: mhagent: unrecognized option '--hh' options=' --aa ...
1
vote
1answer
27 views

if command in find -exec

I was just trying to list all directories and files under current directory and also write if they are file or directory with the following command: find -exec echo `echo {} : ;if [ -f {} ]; then ...
1
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2answers
43 views

Extracting numbers with a decimal point from ls output in Bash

I would like to extract the numeric part of the file names that begin with "hsli" and end with ".h5" in Bash on Ubuntu 14.04.1 64-bit LTS. My ls -l hsli* output is as follows: -rwxrwxrwx 1 ongun ...
0
votes
2answers
29 views

What I am doing wrong with this bash variable? [on hold]

How can I insert a variable into a command? In the case below, I need to concatenate the command with the variable file name. #!/bin/bash # Define a timestamp function timestamp() { date +"%D-%T" ...
1
vote
1answer
34 views

How can I get $PATH to always include $(pwd)/sub_directory/.bin

If the path ~/dev/project1/node_modules/.bin/ionic exists, and my working directory is ~/dev/project1, I would like to be able to just type ionic and hit enter. I could include all those ...
-5
votes
1answer
25 views

Remove characters from string with sed [on hold]

I have this header: >tr|G3Q381|G3Q381_GASAC Uncharacterized protein OS=Gasterosteus aculeatus PE=4 SV=1 and I was thankfully helped on here to get it to: >G3Q381_GASAC but now I need to ...
2
votes
1answer
20 views

Show shell greeter only on initial login

Is there any way to show a greeter (motd kind of thing) only on initial login, and not when you do sudo su? Here's my current .bashrc: #!/bin/bash # # ~/.bashrc # # If not running interactively, ...
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votes
0answers
12 views

PHP execute find + cp from page

I would like to copy some files from one folder to another in a Linux system through the use of PHP's methods exec or shell_exec. Currently, the bash shell executes this line correctly and the files ...
0
votes
1answer
37 views

Detecting function circular references in bash

Why does the following idiom not work in bash 4.1.0? if [[ "${FUNCNAME[*]:1/$FUNCNAME/}" != "${FUNCNAME[*]:1}" ]] Here it is in context... function isCircularRef_test () { # ### Seems like ...
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votes
0answers
43 views

replace first string before first space [on hold]

how to replace first string before first space? NC_009925.1_13653 [754389 - 754574] Acaryochloris marina ATTCCTGATTCTCTTGATGAAAGTAACATTATGGATCAT... TATGATCCATTCAGGCATGATGCAAGGCGCTACCCCCAA... 110311 ...
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votes
0answers
6 views

Specify “any sequence of digits” to ‘compgen’

How can I get compgen to return matches for “any valid sequence of digits”? The Bash compgen command is used to generate completion matches in Bash programmable completion. There are many options for ...
1
vote
1answer
48 views

getopts passing value of declared parameter to function

I have function port.sh as stand alone script and i'm wondering if is possible to put this function in the same script where getopts is and pass value of OPT_B into function and get output of it? ...
0
votes
3answers
44 views

Parent script continues when child exits with non-zero exit code [on hold]

I have a script that calls another script. When the child script fails, I'd like the parent to fail as well. In the child script child_1.sh, I have something like this: if [ $SOME_BAD_CONDITION ] ; ...
1
vote
1answer
41 views

cp with interactive don't prompt before overwrite

I observed a strange behavior cp. Exactly the point is that cp did not ask me for confirmation, even with the option interactive. A test case looks like this Existing files find * -type f ...
1
vote
3answers
67 views

How can I make sudo forget the password automatically after one command?

My problem is the following: I want to edit a file that is only readable by root. That's why I use sudo vim ~/thefile I could type sudo -K after exiting vim, but I was hoping that there's an ...
3
votes
1answer
35 views

Question about interactive detection in bash

I have a question about interactive detection in bash. The following script prints if it is called in interactive mode or not. $ cat int.sh #!/bin/bash if [ -t 0 ]; then echo "interactive" ...
4
votes
2answers
227 views

Delete files older than specific file

I need to delete from a folder all files older than a specific file. Running bash on CentOS 7. I have a solution for this, but I think there should be a more elegant way do it: ...
1
vote
2answers
44 views

print the output of 2 commands in 1 file on the same line

Thanks for looking at this. I have a possible simple question, but I wasn't able to find any help so far on the internet. I have a script that has mainly 2 commands that process output. But both ...