Questions about shell scripts, executable files that are interpreted by a shell (bash, zsh, etc.).

learn more… | top users | synonyms (2)

1
vote
2answers
802 views

Remove all packages in a text file via apt-get

I have a text file with a package on each line. How can I remove all the packages in that text file from the system? Also, if one package cannot be removes/wasn't installed in the first place can I ...
1
vote
2answers
3k views

How to create a md5-file for every folder in a drive recursivley?

I'm searching for a script which creates a md5 chechsum file for every single folder inside drive recursivley? I do have a copy of md5deep on my machine but I'm not that good in scripting bash.
0
votes
2answers
2k views

Deleting many files except one type [duplicate]

Possible Duplicate: Deleting all files in a folder except files X, Y, and Z I am writing a script to compile many .tex files. After that, many auxiliaries files were created. So, I would ...
3
votes
2answers
2k views

exec < filename - what does this do?

I have found the following code snippet (sh): TESTFILE=$TEST_PATH/test.out if [ -f $TESTFILE ] then exec < $TESTFILE else echo "$TEST_PATH: no test.out file" fi ...
3
votes
3answers
612 views

How to remove a trailing CRLF from a file?

I have a binary file with a trailing CRLF (2 bytes total) that I want to remove. How should I do it? Please note that I'm using busybox and I don't have perl.
5
votes
4answers
4k views

Pgrep returns mutiple PIDs

My script accepts a process name as an input and kills it, I tried using pgrep but its returning two PIDs , one for the process which is running and one for the script which accepts the process name ...
4
votes
4answers
3k views

How do you colorize only some keywords for a bash script?

I am running some unit test code. The unit test code outputs regular text. There is a lot of the text so I want to highlight for the user important keywords. In this case the keywords are "PASS" and ...
14
votes
4answers
19k views

How can I use bash's if test and find commands together?

I have a directory with crash logs, and I'd like to use a conditional statement in a bash script based on a find command. The log files are stored in this format: /var/log/crashes/app-2012-08-28.log ...
3
votes
1answer
216 views

Locking in a shell script

I want to write a long-running shell script so that only one copy could be run at a time. If the script crashes, I want a new invocation of the script not to be stopped by a lock from the crashed ...
0
votes
1answer
261 views

How to automatically install packages?

I want to install packages automatically by running a script I can write yum install php, but I want it to install another package once installation of the php package is completed. Is there any ...
0
votes
1answer
222 views

The “cp p2 &2 &” command makes Konsole to disappear, is it a bug?

The goal is start a background process that copies the data from the pipe p2 to the STDOUT as p2 is feed with data by some other process. I guess the command is incorrect. Nevertheless, the Konsole ...
2
votes
3answers
2k views

Switching to superuser while shell script is running

I have a shell script that contains the following lines: CURRENT_USER=${USER} echo $CURRENT_USER su echo switch to `who am i` Once the 2nd line is executed, the shell prompts me to enter the root ...
3
votes
2answers
1k views

How to create multiple zips from a directory containing a million xml files?

I have a directory containing million xml files. I want to create multiple zip files containing n number of xml files. For ex: if n = 10000, then I want to create 100 zip files i.e. each zip file will ...
2
votes
2answers
1k views

How to merge chunks of text files in a directory to one or more files?

I have a requirement to merge chunks of text files in a directory to one or more files and then zip the merged file. For ex: If i have half a million text files in a directory, say A. I want to merge ...
4
votes
1answer
95 views

Transform directory structure

I have the following folder structure root folder |-al2 |- GER.zip |- ENG.zip |-ww |- GER.zip |- ENG.zip and so on. The folder names are random strings. I want to sort the files in ...
1
vote
1answer
414 views

How does “options” in shell scripting work?

I found some code in one of the answers here and accommodated it to my needs but now I have two questions: Q1: how can I display the options text after the code in case statement finishes? So the ...
3
votes
2answers
437 views

rename randomly files on a USB device

I would like to rename all of my files of my USB device randomly. Indeed, in my car, my tuner has not the random function. I think I can do it with PHP ... but I'm pretty sure it is possible to do ...
1
vote
1answer
239 views

Making multiple calls to a program via a bash shell script

Suppose that I have a program make_ndx that outputs via the -o switch. I would like to call myprogram from a bash shell script and output two files, out1.ndx and out2.ndx. (myprogram takes a string ...
1
vote
1answer
2k views

Do shells support recursion?

I'm trying to write recursive functions in my shell scripts. Consider the following code: function printA { if [[ "$1" = 0 ]]; then return else echo "a$(printA $(("$1" - 1)))" ...
18
votes
4answers
40k views

Shell script fails: Syntax error: “(” unexpected

I've been working on a script that automates setting up a development environment for Raspberry Pi development (step by step details that work are here). The script is linked in that article but ...
2
votes
2answers
514 views

Executing zsh rehash after build

I have a build script that can change what binaries are in my $PATH (it doesn't edit $PATH itself, but it adds/deletes files to folders that are already in $PATH). zsh's autocompletion doesn't update ...
2
votes
1answer
158 views

How to have find only search for files in changed directories?

Currently I'm repeatedly doing a 'find' that's too slow. I'm searching for non-hidden executable files within "$root", excluding "$root/bin": find "$root" -type f -perm -o+x -not -path "$root/bin/*" ...
2
votes
1answer
772 views

Extended file globbing not working with cat inside bash script

When, in my terminal, I type cat ~/my/+(a|b)/doc It reads ok from both ~/my/a/doc and ~/my/b/doc, but when I put that command in a bash script: #!/bin/bash cat ~/my/'+(a|b)'/doc I get the error: ...
7
votes
1answer
743 views

Bash script doesn't read input

I have a script that is suppose to run a command in the background, and it does that. The problem is that when the script comes upon a read command, it doesn't pause and accept input. Here it is: ...
2
votes
3answers
1k views

Copy/backup all dirs containing files matching a regexp

I would like to do a backup where I recursively go through a dir structure and only get directories with files whose names matching a particular regexp. I would like to keep the directory structure, ...
4
votes
1answer
1k views

Validate AIX Password for root from script

Looking for a way in a shell script to validate the password for for root on an (AIX) matches a standardized plain text password. This query is similar to another one on this site. I have access to ...
4
votes
2answers
2k views

bash myscript.sh runs in bash, but the first line is #!/usr/bin/sh

I have a script similar following one: #!/usr/bin/sh var="ABC" if [ $var == "ABC" ] then echo True else echo False fi Above code does not work in Solaris Sparc and Solaris X64. It is showing ...
2
votes
7answers
58k views

Adding two numbers using expr

I'm learning Shell scripting for a diploma in IT I'm currently doing. I'm trying to write a small script that adds two numbers as shown as in one of the tutorials we were given. echo "Enter two ...
9
votes
1answer
2k views

Are dash, ash and sh script 100% compatible?

I wanted to know whether scripts written for dash, ash, and sh are 100% compatible? Are there any added features to dash or ash, or syntax change? From what I heard, ash is a direct descendant of ...
1
vote
2answers
395 views

Remove oldest folders + files (50GB) from a folder when share/HD reaches 95% full capacity

I have a big share (~5TB) that is getting full. Now I want to make a script that deletes data from 2 specified folders. But this need to be the oldest files/folders and it need to stop when ~50GB has ...
3
votes
2answers
2k views

When sh is a symlink to bash or dash, bash limits itself to POSIX-compliance, so it should be 100% compatible with sh?

From Difference between bash and sh: ABck to the question: If you have /bin/sh as a link to bash, then bash will not behave the same when called as /bin/sh as it does when called as /bin/bash. ...
6
votes
1answer
320 views

How to find out whether a shell script is written in bash or sh

How can I find out whether a script is written in bash or sh? The first line of the script is not helpful here, since on Linux, bash scripts have this line: #!bin/sh Actually, there are many ...
3
votes
2answers
2k views

Can I run Bash scripts in FreeBSD without modifying them?

Correct me if I'm wrong: "sh" script != "bash" script Linux script are written in Bash Bash script usually #!/bin/sh In GNU/Linux, /bin/sh is Bash In FreeBSD, /bin/sh is not bash, it's the true sh ...
6
votes
3answers
16k views

ssh input from text file

These two question is driving me crazy and I don't have good expertise of ssh. (but I suspect it is to do with redirection only) The questions are, You want to pass multiple lines of input from a ...
6
votes
2answers
3k views

assign shortcut key to run a script

I've written a script to change the brightness of my screen. It's useful when I am working on text mode and shortcut keys of my keyboard to change brightness doesn't work. Is it possible to run this ...
3
votes
3answers
4k views

Shell Script to Execute Shell Script to All Subdirectories

I am making a script to simplify my daily tasks. Everyday, I have to grep for a few things inside a company server. It was okay, however, now, they have segregated each object into sub directories. I ...
1
vote
1answer
437 views

Identify remote windows server from shell script

I need a way to Identify a windows SBS server, I have a script that mounts a file share on a SBS server, I need the script to positivity identify the server before mounting. It doesn't need to be ...
6
votes
2answers
5k views

Why does `exec 2>&1` fail in this bourne shell script?

I am porting an old ksh script to Bourne shell. The old ksh script contains the following code: #!/bin/sh tmpLog=/var/tmp/logfile.$$ exec 1> $tmpLog exec 2>&1 eval $* another_command_1 ...
2
votes
1answer
878 views

Assigning command output to variable gives strange results

My script looks like this: #!/bin/sh PROJECT_DIR=$(cd -P -- "$(dirname -- "$0")" && pwd -P) COMMANDS_CODE=$(php $PROJECT_DIR/bin/console generate:code) echo $COMMANDS_CODE The output has ...
1
vote
2answers
1k views

On the command line, can I redirect output to a file WITHOUT >, >>, or | operators?

I am attempting to run a command on a CentOS virtual machine, and the API that I am using to run this command does not seem to allow the >, >>, or | operators. Also, I must use fully qualified paths ...
0
votes
0answers
2k views

bad magic number

I have a script which I need to execute. The script file is push.sh. Below are the commands that I am using: dragan@dragan-Lenovo-G570:~/liquibase/liquibase$ chmod +x push.sh ...
11
votes
4answers
21k views

printing colored text using echo

I know that for printing a colored text using echo, for example red color, the code is: echo -e "\e[1;31m This is red text \e[0m" and I know that in this example, 31 is code of red color and the ...
18
votes
5answers
27k views

How to introduce timeout for shell scripting?

I want to run a shell script that got a loop in it and it can go for ever which I do not want to happen. So I need to introduce a timeout for the whole script. How can I introduce a timeout for the ...
3
votes
2answers
2k views

How to solve sudo: unable to execute /bin/ls: Argument list too long

When I run this command from php sudo -u db2inst1 ls -t /var/lib/edumate/bdrs/*/*/daily/*NODE* | sort -r I receive sudo: unable to execute /bin/ls: Argument list too long ls lists all daily backup ...
18
votes
1answer
780 views

Is there a standard command that always exits with a failure?

I want to test my script with a command that fails. I could use an existing command with bad arguments. I could also write a simple script that immediately exits with a failure. Both of these are easy ...
2
votes
0answers
500 views

Validate Password for user account from shell script

Application is for a multiple server standardization script Looking for a way in a shell script to check if the password for an OS account (AIX) matches a standardized plain text password. The ...
29
votes
4answers
6k views

How to do nothing forever in an elegant way?

I have a program which produces useful information on stdout but also reads from stdin. I want to redirect its standard output to a file without providing anything on standard input. So far, so good: ...
4
votes
1answer
188 views

Discard stdout of a command for t seconds

I am working on some batch scripts involving the following: Run some non-terminating sub-processes (asynchronously) Wait for t seconds Perform other task X for some time Terminate subprocesses ...
15
votes
2answers
5k views

Are there naming conventions for variables in shell scripts?

Most languages have naming conventions for variables, the most common style I see in shell scripts is MY_VARIABLE=foo. Is this the convention or is it only for global variables? What about variables ...
5
votes
3answers
12k views

Automating textual input from a bash script without using EOF

I'm running Ubuntu Linux. Suppose there is a program called myprogram. This program prompts the user for input; specifically, the user must type an integer when prompted and press Enter. I would ...