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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2
votes
1answer
517 views

Exiting a Bash script when a sudo child quits

I'm trying to launch a couple of sub-programs from a bash script and then wait on either of them to quit before quitting the other and exiting the script. CMD1PID= CMD2PID= exit_trap () { ...
2
votes
2answers
103 views

scripted pdf code review

What I try to achieve I need to review a bunch of C source code spread out into dozen of directories. I already have a bash script which does the following: It searches for all source codes in the ...
0
votes
1answer
432 views

from iostat -En output ,i need to display Hard Error more than 2

I am a Customer service engineer for solaris. But I am new to shell scripting, I need to display the lines which are having Hard Errors more than 2 from the output of iostat -En | grep Hard in case of ...
0
votes
1answer
4k views

Trying to cp a path with spaces, fails when scripted but echoing and pasting succeeds? [closed]

I have a script that is trying to copy a directory from a path that includes backslash-escaped spaces and is stored in a string variable to a subdirectory of the working directory. When I run the ...
2
votes
1answer
93 views

Using 'convert' with files that has space characters?

for f in $(ls mydir/*.jpg) do convert -thumbnail $size -quality $quality $f thumbsdir/$(basename $f) done I'm trying to code a script that takes a directory with images and generates thumbnails ...
3
votes
1answer
594 views

bash environment - pasting strings with “special” characters

I'm using an application and I need to paste a string into the app... e.g ãµÜÇæ¢üäÄøqò When I login with bash shell it's impossible to paste the string with the special characters. If I change the ...
6
votes
4answers
743 views

How do I stop bash from hanging when trying to start programmes while NFS is disrupted

I am currently experiencing a bug in Ubuntu 13.10 which means that when I resume my machine after a suspend, the network connections do not come back up. I have a couple of NFS mounts and because they ...
3
votes
3answers
1k views

Adding prefixes/suffixes to file names without typing it all over again?

I would like to do something like the following $ tmp=name* $ mv $tmp new_$tmp $ ls new_* $ new_name-with-stuff-i-dont-want-to-type name-with-stuff-i-dont-want-to-type Setting the environment ...
6
votes
1answer
419 views

Change the location of .bashrc

Is it possible to change the location of .bashrc from /home/orhanc/.bashrc to some other directory?
2
votes
2answers
403 views

What is the use of “&>>” in bash?

I was studying a bash script code where I encountered operator "&>>". I didn't understand its use. So, I referred to http://www.gnu.org/software/bash/manual/html_node/Redirections.html . It is ...
5
votes
2answers
904 views

Why does Bash history not record this command?

The command printf "#!/bin/bash\n" > t generates an error(bash: !/bin/bash\n": event not found), but hitting the up key does not recall the command so that I can modify it. Why is that? (What I ...
2
votes
3answers
125 views

How to create a function based on commands not defined yet?

I have some scripts (that are out of my control) that loads some environment settings to my session. So whenever I want to load I have to execute a series of commands: export ...
7
votes
3answers
23k views

How do I set permissions recursively on a dir (with ACL enabled)?

For example, I want to give my colleagues write access to certain directory. Let's assume that subdirectories in it had access rights 775, files 664, and also there were some executable files in the ...
1
vote
4answers
5k views

How do you create and execute a bash script which calls an executable from higher folder?

I'm attempting to write a very simple script which calls an executable from a higher level folder. If I were just typing the command into the console, I would type ../filenamehere {options} ...
5
votes
2answers
1k views

How do I filter a log to only the lines between two times?

I'm working in Unix. I'd like to fetch information from a log in a specified time range for the current date. For example I want the data from a log file of today's date from 00:00 to 09:00. Sample ...
0
votes
1answer
3k views

LFTP mirror upload only non existing files to remote directory

Every 5 minutes some new files are downloaded via lftp to a local directory. I need to upload to another ftp only the non existing files. My script so far is: #! /bin/bash today=$(date +%Y%m%d) ...
26
votes
5answers
25k views

Why do we need the “at” command in Linux?

I was studying code in which the at command is used. I looked around and found that it is used to execute batch jobs. It is used to schedule jobs. It is given, as its input, a command, and a time, ...
1
vote
3answers
69 views

return the numeric value of a indexed variable rather than its name [duplicate]

The following piece of code illustrates my problem I'm afraid I oversimplified it way too much in the first round. #!/bin/bash dogLover=1 catLover=2 for ii in dog cat do ...
1
vote
2answers
1k views

Bash completion throwing syntax error

THE PROBLEM: Say I'm trying to change to a directory called 'build' which is in the directory I'm currently in. I start: cd b Then I hit tab once (knowing that no other directories in the current ...
2
votes
2answers
1k views

Need to copy files to existing directory and remove files already there with the same name but different extension

EDIT: Total rewrite of question for clarity. I have a directory tree (new) with a bunch of files of with an extension of .new. I have an identical tree (old) where many of the files have names ...
4
votes
1answer
765 views

Array Cartesian product in bash

Is there a way to generate cartesian product of arrays without using loops in bash? One can use curly brackets to do a similar thing: echo {a,b,c}+{1,2,3} a+1 a+2 a+3 b+1 b+2 b+3 c+1 c+2 c+3 but I ...
1
vote
3answers
2k views

Batch file move to directory structure based on filename

I am writing a script to move files into directories based on the filename. Files have yyyyddmm-xxxxxxx.jpg name format. The desired directory structure is in the format 2013/01 Jan/31. I am unable ...
3
votes
2answers
3k views

How to find frequency of occurrences of strings contained in a file?

I have a file that contains a list of URLs of the form EDIT http://www.google.com/absd/siidfs/kfd837382$%^$&, www.google.com, google.com yahoo.com/list/page/jhfjkshdjf... I ...
2
votes
2answers
10k views

integer expression expected bash

Trying to loop a phrase inputted by the user a set amount of times that is also inputted by the user. Keep on getting the error integer expression expected, and I can't figure out how to fix it. ...
1
vote
2answers
492 views

Get scan codes in octal format

Using showkey -s I can get the scancode of a key as a hex-number. How can I get it directly as an octal number?
25
votes
6answers
4k views

Pipe to multiple files in the shell

I have an application which will produce a large amount of data which I do not wish to store onto the disk. The application mostly outputs data which I do not wish to use, but a set of useful ...
3
votes
1answer
150 views

Finding a char device in /sys using a Bash script?

I have one of these and I am trying to write a Bash script for finding the device path in /sys. My approach goes something like this: start in /sys/modules/usbled since this is the name of the ...
1
vote
1answer
2k views

ssh with sudo doesn't start services

I want to run command with sudo through ssh without disabling "requiretty" sudo option. According to /etc/sudoers: # # Disable "ssh hostname sudo <cmd>", because it will show the password in ...
6
votes
3answers
3k views

How to inspect group permissions of a file

I would like to inspect group permissions of a file from a bash script. Specifically, I need to check whether a file has the group writeable bit on. That's it. Simple as that. However: I also need ...
15
votes
2answers
2k views

Are quotes needed for local variable assignment?

Can I safely omit quotes on the right side of a local assignment? function foo { local myvar=${bar} stuff() } I'm mainly interested in bash, but any info on corner cases in other shells are ...
2
votes
2answers
2k views

find: combining -path and -prune to exclude files and directories

I have a directory /srv/tftp/pxelinux.cfg and a file /etc/mtab. I want to exclude both from find. But whatever I do, either one always is not excluded find /etc /srv -path /srv/tftp/pxelinux.cfg ...
2
votes
2answers
91 views

Different error messages when using different strings in terminal

When I insert, for example, unix.stackexchange.com followed by Enter in terminal, I get the following error: unix.stackexchange.com: command not found This is ok and as I expected. But when I insert ...
0
votes
1answer
108 views

Am I running Bash?

I am using OS X 10.8.5. I am trying to figure out if the terminal is running bash. When I type in the following it says "getent" command not found -- but the error message seems to be coming from ...
5
votes
3answers
221 views

What is the difference between [.]* and '.*' for command 'find -name'?

My goal is to find all files or directories in a filesystem that start with a dot (.), for example .gnupg. So I came up with the command: find -name '.*' Checking on the Internet, I saw some hints ...
6
votes
2answers
6k views

Need to get the difference between two time in seconds

The following two variables contain the start time and the end time , need to get the difference between these two time in seconds start_time=06:07:25 end_time=07:02:08 Desired Output diff_time= ...
0
votes
2answers
597 views

Cannot create root jail

I just tried to play around with chroot command only for testing purposes, in order to create a temporary root jail, but I didn't managed to. The platform is CentOS 6.4. and I have done it numerous ...
2
votes
1answer
953 views

What command will generate average lines per minute?

I'd like to know how many average lines are written to a file per minute. Could someone help me with a command or code to generate this number?
3
votes
3answers
125 views

'Binding' Bash Curly Braces

In Bash, echo a{b,c}d{e,f} prints abde abdf acde acdf The output I'd like to see is abde acdf In other words, given N parameters, I'd like Bash to use the ith parameter within ...
0
votes
0answers
36 views

How to use grep command to find the matching pattern and some more characters? [duplicate]

I have a compressed JS code and I want to find a pattern, but since the file is compresses, it has only a line, and the match pattern is all the file. The output is too much large. grep -r ...
5
votes
5answers
21k views

How to catch an error in a linux bash script?

I made the following script: # !/bin/bash # OUTPUT-COLORING red='\e[0;31m' green='\e[0;32m' NC='\e[0m' # No Color # FUNCTIONS # directoryExists - Does the directory exist? function directoryExists ...
26
votes
9answers
2k views

for vs find in Bash

When looping through files there are two ways: use a for-loop: for f in *; do echo "$f" done use find: find * -prune | while read f; do echo "$f" done Assuming these two loops will ...
19
votes
4answers
7k views

Why does while [ 0 ] go into infinite loop?

I see the same behaviour for below loop as the loop with while [ 1 ]. Why is that so? while [ 0 ]; do echo "hello" done
3
votes
2answers
1k views

Suppress “Alarm clock: 14” from ping

I've made a simple script for rebooting my router and afterwards showing a progress bar until my computer has an internet connection again. When running the script I get the following output: The ...
3
votes
3answers
296 views

How can I list all files and symlinks in a compact view?

This is my setup in /tmp/test/ if I use ls -l -rw-r--r-- 1 rubo77 rubo77 0 Okt 21 04:15 a -rw-r--r-- 1 rubo77 rubo77 2 Okt 21 04:16 b drwxr-xr-x 2 rubo77 rubo77 4,0K Okt 21 03:58 c ...
20
votes
2answers
34k views

How do I check if a file is a symbolic link to a directory?

I can check, if a file exists and is a symbolic link with -L for file in *; do if [[ -L "$file" ]]; then echo "$file is a symlink"; else echo "$file is not a symlink"; fi done and if it is a ...
1
vote
1answer
640 views

while loop is running only once?

I am trying to make a clip out of video file by playing it only for certain interval. make_mclip.sh #!/bin/bash mediafile=$@ mediafile_fullpath=$PWD/./$mediafile tmpedlfile=$(mktemp) mplayer ...
0
votes
2answers
188 views

why does `awk` fail when I put it in a bash script

on the prompt: ls | awk '{printf("%s\t\t%s\n", $9, $3);}' succeeds in printing what it is supposed to be printing. If I put it in a file, I get four or five empty lines (about the number of lines ...
1
vote
2answers
449 views

Execution of a command in a variable with eval

I am trying to use grep to color some log files . I wrote a script and a part of it looks like this : #!/bin/bash com="GREP_COLOR=\"1;36\" egrep --color=always '[^a-zA-Z0-9]' $log |less -R" ...
1
vote
2answers
1k views

How do I get the nc command to end after 2 seconds? [duplicate]

I have to write a maintenance script that iterates over our IPs testing their connectivity to certain services such as nc -sip# mailin-01.mx.aol.com 25. It has a flag -w ... but it's not what I think ...
2
votes
2answers
3k views

Using for loop to brute-force a password

I just wanted to brute-force my old router but the for-loop was really amateur style. How to write a nice for-loop, if I only know the charaters included? Found already that page but it does not ...