11
votes
5answers
288 views

Stateful bash function

I’d like to implement a function in Bash which increases (and returns) a count with every call. Unfortunately this seems non-trivial since I’m invoking the function inside a subshell and it ...
4
votes
2answers
48 views

Script to loop through folders with numeric names

I am working on a bash script to compress the images in my Wordpress folders. The wordpress folder structure is as follows: > wp-content/uploads/2014/01/filename.jpg > ...
11
votes
3answers
298 views

Variable as command; eval vs bash -c

I was reading a bash script someone made and I noticed that the author doesn't use eval to evaluate a variable as a command The author used bash -c "$1" instead of eval "$1" I assume using eval ...
5
votes
2answers
198 views

Get the actions for a command programmatically

Let's take the git example: $ git<TAB><TAB> git git-import-dscs git-shell git-buildpackage git-import-orig git-upload-archive git-dch git-pbuilder ...
1
vote
2answers
54 views

copy files from one path to another path in linux

I am new to linux. I am trying to copy files from one path to another path. I have a text file which has all names of files in the following pattern: file-1.txt file-2.pdf file-3.ppt .... I created ...
1
vote
2answers
53 views

Editing a Java properties file with Bash

I have the following Java properties file that is maintained by humans. # file.input = /very/old/name # file.input = /old/name file.input = /current/name file.input.default = /default/name ...
0
votes
2answers
33 views

command condition sometimes integer sometimes string

I want to execute this condition while [ $(cat /path_of a file/) -eq 1 ] The condition is only correct if $(cat /path_of a file/) is an integer and not a string ! How can I overcome this ...
1
vote
2answers
43 views

Bash: split list of files into different files?

I have several files in a directory like: data1.dat data2.dat .... data24678.dat To run another code, I need to have a text file with the names of the files but I need to split in 50 files per ...
4
votes
2answers
75 views

How to kill a process started as daemon?

I start a process using foo &. It outputs something like: [1] 16915 This is the process id, I guess. How can I store this number into a variable named MY_PROCESS_ID (for example)? Then I ...
3
votes
1answer
28 views

How can I tell whether a package is installed via yum in a bash script?

I am trying to write a script that installs packages, but if it fails at any point later in the script rolls back whatever it installed. Of course if the user has already previously installed a ...
0
votes
2answers
52 views

Bash split a list of files

I have 200 files in a folder like: test_1_cfg.dat, test_2_cfg.dat,.... and so on. I need to include in a bash script the first 40 files as input and run some process, another script to read the next ...
3
votes
3answers
74 views

Bash, how to let some background processes run but wait for others?

I have (yet) another wait, &, && control flow question.. Say I have a script something like this where I want to do as much work at the same time as possible: # may take some hours ...
0
votes
2answers
46 views

bash function output to pipe [closed]

I made a bash function to beautify svn output, this function show logs one line per commit, it is great! I like it, but if I use it with pipe it does not work. You can find it on github svn-beautify ...
1
vote
1answer
68 views

Date calculation in script for notification alerts

I want to create account expiry alerts therefore I need to write a script which could alert me before 1 month of expiry over email. I'm working on Linux. I can get expiry information as 2015-27-03. ...
10
votes
7answers
251 views

Test if multiple variables are set

I'd like to make sure that at a certain point of a script, after sourceing a configuration file, several variables are set and, if they are not, to stop execution, telling the user about the missing ...
4
votes
2answers
109 views

Convert every pdf in the current directory to png

I want to write a bash script to convert every .pdf file in the current directory into a .png file. For example: $ls . a.pdf b.pdf $./pdf2png.sh Converting pdfs to pngs a.pdf -> a.png b.pdf -> ...
2
votes
5answers
288 views

How to reverse a string made of digit in bash?

What is the best way to turn out digits in number? E.g. $ echo 123 | hook 321 $ echo 12358 | hook 85321
3
votes
2answers
40 views

Bash script : help file inside the script or in a different file?

I'm writing a script that has the vocation to be a fully featured program at the end. As far as I know, BASH is enough for his purpose (manage PPA's, kinda like Y-PPA). I would like to know how to ...
1
vote
2answers
44 views

Bash script is not working

I wanted to create a script that executes the ls command with the provided arguments. Why isn't it working? I tried running it with for example -R, then it echoes (I echoed the same thing for ...
2
votes
2answers
50 views

I want a script which will take multiple column numbers from a user and reverse the contents

I want a Unix script which will take multiple column numbers from the user and reverse the contents. declare -a param="$@" # enter 0 when exit the insert element echo "Enter the numbers" read n while ...
2
votes
1answer
87 views

Bash Script getting stuck during execution

I have a bash script that is reading a CSV file , that contains source IP address , destination IP address and destination port. My script is basically doing 2 tests: 1 Performance 2 Connectivity. ...
2
votes
4answers
100 views

Parsing process command-line arguments from pargs in a shell script

I get list of PIDs in my bash scripts (Java processes) and have to analyze their command-line arguments to determine which instance of server each PID corresponds to. At the moment I do it that way ...
21
votes
7answers
811 views

Should scripts that require sudo fail if they don't have it, or use sudo and prompt?

I have a script which gives me fine-grained control over my backlight brightness and requires sudo to run. It's essentially this: backlight="/sys/class/backlight/acpi_video0/brightness" echo $1 | tee ...
3
votes
1answer
665 views

What's the difference between “==” and “=~”?

Given a string and a hash returned by openssl, why using == doesn't match them correctly but =~ does? Background question: How can I force a script to use more resources?
-4
votes
3answers
127 views

How to get IP Address using shell script? [duplicate]

Want to get the IP address using Shell script. Without knowing the eth0 or eth1 or eth2 How to get the particular IP address. I am not interest to get localhost address, want to get private IP ...
-4
votes
4answers
83 views

How to add a 3 lines in a file using shell script? [closed]

I have a file, that file contain 10 lines. And now I want to add 3 lines to end of the file using shell script. After add lines, If I run the script again I don't want to add same lines again. ...
2
votes
4answers
114 views

Bash script to output path to USB flash memory stick

How would I return (output) the path to any USB flash memory stick(s) connected to the local computer using bash (Ubuntu and Linux Mint)? Background: I'm providing users with an automated backup ...
0
votes
2answers
77 views

How to write an alias function to make dd show progress bar?

According to this article, by replacing: $ dd if=/dev/sda of=/dev/sdb [additional options] with: $ pv -tpreb /dev/sda | dd of=/dev/sdb [additional options] one can augment the default dd ...
6
votes
4answers
257 views

Check if $REPLY is in a range of numbers

I'm writing a shell script for Linux, using Bash, to translate any video-file into a MP4. For that, I'm using avconv with libvorbis for audio. Inside my script, I have a question for the user : ...
-1
votes
1answer
42 views

Remove directory without `rm -r`

How to remove non-empty directory without using rm -r or find -delete ? I think it is related to unlink, perl or inode
6
votes
3answers
256 views

Remote ls on multiple machines

I want to connect to multiple machines specified in a file and perform 'ls' there. That's what I've come up with: for machine in $(cat machines) do echo "Connecting to " $machine ssh $machine ...
9
votes
2answers
839 views

Fastest way to concatenate files

I've got 10k+ files totaling over 20GB that I need to concatenate into one file. Is there a faster way than cat input_file* >> out ? The preferred way would be a bash command, Python is ...
-2
votes
2answers
72 views

Input validation in a bash script [duplicate]

I've got the basics of bash scripting (I think anyways), and i'm trying to move on to more advanced stuff. I am trying to write a script that will perform input validation (the user must input either ...
3
votes
1answer
58 views

measure amount of data read from /dev/random

background I have written a collection of bash scripts (most of them in German only yet but if you are interested; download the archive not the single scripts) which help users create high-quality ...
1
vote
2answers
141 views

bash script error: source: not found

I must be missing a fundamental understanding about sourcing files in bash. I've tried the different approaches that seem like they should work, but I still get this error source: not found. In my ...
2
votes
2answers
152 views

Read non-bash variables from a file into bash script

My bash script needs to read the variables from a text file that contains hundreds of variables, most of which conform to standard bash variable sytax (e.g., VAR1=VALUE1). However, a few lines in this ...
3
votes
2answers
112 views

Moving large numbers of files and directories to a different directory

I'm trying to move the following move a large number of files that exist in the following structure to a /mnt/originals but I need to maintain the structure at the same time. I know cp would be a ...
5
votes
3answers
89 views

reliable return code of background process

Let's assume the following piece of bash code: foo > logfile 2>&1 & foo_pid=$! while ps -p$foo_pid do ping -c 1 localhost done wait $foo_pid if [[ $? == 0 ]] then echo "foo ...
0
votes
1answer
41 views

Combining two bash scripts by adding flags

I have two scripts which transform the code from software v.1 to software v.2 and viceversa. These are essentially a lot of sed substitutions. In the way I wrote them they accept two arguments: ...
4
votes
2answers
129 views

Dump process's stdin and stdout

I have two processes, let's say Parent and Child. Parent launches the Child and communicates with it through child's stdin and stdout. Parent <-> Child These processes use text protocol and I ...
4
votes
2answers
107 views

Shell Script to isolate files scattered in different folders

I need to write a shell script that traverses a given directory structure in multiple levels, recognizes the video files scattered in the folders and copies all of them to another single folder. The ...
6
votes
1answer
175 views

Parallel execution of bash script

I have a table URL_Experiment in my database (mySQL database). I have 2 million URL links in this table. For each URL, I am checking if some particular text is present in the URL and updating the ...
-2
votes
1answer
28 views

Implementation Logic [closed]

I have two files,which is something like this: file1 msgid "New" msgstr "" dsvhuvchvdhcvhc msgid "Old" msgstr "hsvhs" kdnvcjdbvj msgid "Bold" msgstr "" file2 dcbjdsbc msgid "New" msgstr "Alas" ...
0
votes
2answers
77 views

Bash script to convert all *flac to *.mp3 with FFmpeg?

I want to convert all *.flac to *.mp3 in the specific folder. This is what I've tried, but not works: # change to the home directory cd ~/music # convert all *.flac files ffmpeg -i *.flac -acodec ...
0
votes
1answer
32 views

Getting a delimiter issue while executing the script

I am creating a test.sh file and i am running it as ./test.sh: string="hello" ed << EOF e any_file 1i ${string} EOF can anybody help me what it does? I am getting some delimiter issue. Can ...
5
votes
1answer
94 views

counting multiple patterns in a single pass with grep?

I've written a grep loop to iteratively count DNA trinucleotides within a gzipped DNA fasta file containing DNA sequences e.g. declare -a tri=(AAA AAC AAG AAT CAA .. etc) for i in ${tri[@]} do ...
1
vote
2answers
41 views

Make Trickle get the correct $PATH

Trickle is a bandwidth limiting program. I have the following script for trickle. #!/bin/bash echo $PATH trickle -s -t 3 -u 200 -d 200 "$@" I have a script in ~/bin/ that want to run the script ...
0
votes
1answer
133 views

Basic script in Angstrom Linux running on a Beaglebone Black

On my embedded system, I can toggle a user led with: echo > 1 sys/class/leds/beaglebone:green:usr2/value. Similarly, I can find the value of a GPIO (gpio60) (set to input), with more ...
1
vote
3answers
78 views

Script to split string

@terdon's answer provides this script: find . -type f -name "*mp3" | while read file; do album="$(basename "$(dirname "$file")")"; filename="$(basename "$file")"; ...
0
votes
1answer
225 views

“Expect” automation tool output to shell variable

#!/bin/bash # more commands here expect << EOD spawn telnet localhost 9151 expect -exact "Trying 127.0.0.1...\r Connected to localhost.\r Escape character is '^]'.\r" send -- "AUTHENTICATE ...