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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5
votes
4answers
487 views

Accidental `nano SomeFile | uniq` renders the shell unresponsive

In my attempt to get unique entries (read lines) out of a simple text file, I accidentally executed nano SomeTextFile | uniq. This "instruction" renders the shell (bash) completely (?) ...
2
votes
3answers
253 views

Zip output formatting

I'm learning zip and I have run into something I cannot figure out in man zip. When I run zip -r $folder $folder it will correctly zip all contents but the zip contents is as follows: zip |-folder ...
0
votes
1answer
948 views

Where to find printf formatting reference?

Where is the offline reference of the format specifiers (e.g., %i, %s) which are supported by the Bash/system printf command? I've looked in help printf, man 1 printf and man 3 printf without luck. ...
6
votes
1answer
695 views

Running parallel bash jobs on a HPC cluster using GNU parallel

On an HPC cluster I am trying to run multiple bash scripts (permute2.sh) from 1 bash script using GNU parallel, however it doesn't complete every job. It randomly completes one job, while it is stuck ...
2
votes
1answer
238 views

Delete every users from a group

I search a clean way to delete every users from the 'sudo' group. On several distributions the user created during the installation process has sudo rights, I don't want this. I search for an ...
2
votes
2answers
588 views

Awk to output read file

I havent stepped into awk yet but it is on my plate for learning this coming year. I asked a previous question that led me to awk and it works. However, I am unsure how to input all file types and ...
5
votes
5answers
187 views

How to create directory ranging from 1 to nth?

In my scenario, I have some photos and I want to keep them seperate. At present I am doing mkdir gallery1 gallery2 gallery3 gallery4 gallery5 gallery6, this is a pain. I think we can do it easily as ...
0
votes
1answer
139 views

Where can I find historical documentation for bash?

Are there any sources for documentation for old versions of some GNU software, in this case particularly bash? I have a embedded system that is running bash 3.00.16, and I'm trying to do some shell ...
2
votes
4answers
429 views

Remove large chunks from json using vim

I have a huge file (1/2 million lines) of json. I need to delete a set of entries that contain a certain string. { "bla1": { "Part1": "Plop1", "Part2": "Plop2", "Part3": ...
0
votes
1answer
1k views

Bash script to copy *.log files into a new directory

I have some files like this: 2012-12-17_083213_1.log 2012-12-17_083213_1.log_stats 2012-12-17_083213_1.logaccount_ptr 2012-12-17_083213_1.loginitial_ptr 2012-12-17_083213_1.logptr ...
16
votes
4answers
20k views

How to view the output of a running process in another bash session?

I have left a script running on a remote machine from when I was locally working at it. I can connect over SSH to the machine as the same user and see the script running in ps. $ ps aux | grep ...
5
votes
3answers
223 views

Coloring output of forked processes

I have a runscript that starts some processes and sends them to the background mongod & pid_mongo=$! redis-server & pid_redis=$! # etc. All these processes then output concurrently to ...
1
vote
5answers
2k views

Identify folder in bash

I was trying to learn how to identify only folders within a folder on the main level. example: main -folder 1 -folder 2 -folder 3 I started with this script: #!/bin/bash ...
3
votes
2answers
1k views

Environment variable set but not respected

I find the following behavior a little confusing, can someone please explain why it happens? In /etc/bash.bashrc I have: EDITOR=vim And it is indeed set: lev@home ~ $ echo $EDITOR vim I would ...
4
votes
2answers
3k views

Shellscript to print a directory tree and files's contents with a nice presentation

I'm trying to write a shellscript which prints a tree-view for a specific directory and it's subdirs to pdf via latex, as well as the titles and contents of all scripts contained within that primary ...
2
votes
2answers
114 views

Are any files loaded when a terminal session terminates?

I know that .profile / .bash_profile are loaded when a terminal session is started, either through local machine or SSH. Are there any files that are loaded/called when the session terminates? ...
6
votes
3answers
7k views

Is there a way to call a command with a set time limit and kill it when that time passes? [duplicate]

Possible Duplicate: Run a command for a specified time and then abort if time exceeds I was working on a continuos integration build script when a need for such a command arose. Basically ...
0
votes
2answers
401 views

/: is a directory issue in bash

I'm quite new to bash scripting and have been going reasonably well but have run into an issue. I am trying to create a script that uses a forward slash (/), however, I keep getting the error message ...
1
vote
1answer
531 views

What is difference between POSIX and bash and other shell scripts?

While going through many answers on Unix.SE, I come across many of them writing their contents w.r.t to Posix or Bash or some other standard. I know of some differences like some have arrays and some ...
7
votes
5answers
12k views

Difference between printf and echo in bash

What is the difference between the printf function in bash and the echo function? Specifically, running: echo "blah" >/dev/udp/localhost/8125 did not send the "blah" command to the server ...
4
votes
2answers
3k views

How do I pass the contents of a file as a command line parameter

I am storing a file path in a file and need to pass the contents of that file as an argument to a shell script, specifically Maven, something like so: mvn -Dvar_name=(contents of file) Would this ...
0
votes
1answer
91 views

Understanding output redirection?

Is it correct to say that the only difference between the 'input redirection operator' and the 'pipeline operator', is that '<' redirects standard input from a file, and '|' redirects input TO a ...
1
vote
1answer
404 views

curly braces and subshell

I can't figure it out. As I read in documentaion, {} doesn't create a subshell. However, looks like that sometimes it does: $ unset T; echo "T_bfr=$T"; echo $$; { echo $$; export T=1; }; echo ...
0
votes
1answer
99 views

Machine data not displaying every 15 Seconds

The following script is meant to output "vmstat" for example every 15 seconds, but for some reason it only does this if there's activity or when I kill the script, in other cases it just sits there. ...
3
votes
1answer
99 views

Mapping character keys

I really don't understand bash's use of control characters. I understand simple things like adding colors with escape sequences but am at a loss for how to do things like bind keys in .inputrc. For ...
2
votes
2answers
4k views

grep output of expect script

I'm trying to run some expect language, and grep/parse the output all in one script. I want to grep the output of and look for "error" (I should note that standard linux commands like awk, sed, grep, ...
0
votes
1answer
494 views

linux + perl + replace any WORD in file with special characters with condition

Example1 work fine when I want to replace OLD_TEXT with NEW_TEXT ( its replace also all special characters as $@^%)(_+`:; etc ..) example1 export OLD_TEXT='$$OLD_WORD$$' export ...
0
votes
0answers
28 views

question about a 'while' logics error [duplicate]

Possible Duplicate: Why is my variable being localized in one ‘while read’ loop, but not in another seemingly similar loop I have a bash script that scraps URLs to feed a MySQL database. In ...
5
votes
1answer
855 views

Difference between environment variable and shell variable

It is said that environment variables are inherited in child processes but shell variables are not. However the following test shows shell variables are seen in child process just as environment ...
0
votes
1answer
3k views

What is the fastest way to process line by line in bash? [duplicate]

Possible Duplicate: How to loop over the lines of a file? Let's say I cat a file and I want to run a bash command on each line and write each line as output. How can I run a bash command ...
4
votes
1answer
2k views

Where does the “export” command come from?

Why doesn't the whereis command give any information about the export command? How does the export command work even if the shell path variable is set to null?
2
votes
1answer
165 views

variable assignment and IFS

Per Greg's Wiki the IFS variable is used: In the read command, if multiple variable-name arguments are specified, IFS is used to split the line of input so that each variable gets a single field of ...
10
votes
2answers
3k views

“trap … INT TERM EXIT” really necessary?

Many examples for trap use trap ... INT TERM EXIT for cleanup tasks. But is it really necessary to list all the three sigspecs? The manual says: If a SIGNAL_SPEC is EXIT (0) ARG is executed on ...
4
votes
4answers
3k views

execute bash script inside .bashrc

Hi I am curious if it is possible to execute a bash script inside bash rc. It would seem to create a infinite loop unless there was some way to tell it to not try and start a new shell. Here is an ...
0
votes
3answers
525 views

Increment xml files with bash

A good mate on a forum had helped me with creating this script but everything Ive thrown at it outputs wrong and I do not know why or what is the issue. I ran all my script in ubuntu's terminal if ...
8
votes
3answers
3k views

How to delete commands in history matching a given string?

I need to delete all commands in my history matching a string. I've tried: $ history | grep searchstring | cut -d" " -f2 | history -d -bash: history: -d: option requires an argument $ history | grep ...
5
votes
2answers
7k views

Trouble in script with spaces in filename

I've got a script that scp's a file from remote host back to local. Sometimes the file names contain spaces. scp does not like spaces in its file names. For some reason my attempts at handling the ...
2
votes
4answers
2k views

How to rename files with sed and csv

I'm new with Linux, sed, and awk but I don't mind challenging myself on new ideas. That being said, I understand the purpose and how to use rename and sed for a common event such as adding a $date or ...
2
votes
3answers
2k views

Substitute placeholders in template

Say I have a shell configuration file config like this: HOST=localhost PORT=8080 Now I have a template template like this: The host is <%= @HOST %> The port is <%= @PORT %> How do I ...
3
votes
2answers
1k views

Keep all commands in bash history?

I have the opposite question to this. How do I keep all commands in bash history? In Ubuntu since quite some time now, the default for bash is to forget commands with non success exit code. This is ...
3
votes
1answer
999 views

Unix User Level Keylogger

I need to record my own keystroke data for some academic research. I wrote a regular keylogger for Windows, but now I need to write one for a Unix environment, with the constraint that I have only ...
3
votes
2answers
1k views

Why can't I kill a timeout called from a Bash script with a keystroke?

[Edit: This looks similar to some other questions asking how to kill all spawned processes – the answers all seem to be to use pkill. So the core of my question may be: Is there a way to propagate ...
4
votes
1answer
842 views

How to utilize XDG directories and paths in Bash?

I wonder how to access not only the variables defined in ~/.config/user-dirs.dirs with xdg-user-dir, e.g. "$(xdg-user-dir VIDEOS)", but also the following standard variables: ...
0
votes
1answer
131 views

run-parts ignores jobs.deny

I use run-parts to run all scripts under a directory,the same way crontab does. But the jobs deny and jobs allow don't block any of the scripts in the directory. rajeevs@rajeev:/home/rajeevs/test$: ...
6
votes
2answers
2k views

Have cron email output to MAILTO based on exit status

I have a cron job running a php command like this: php /path/to/script.php > dev/null This should send only STDERR output to the MAILTO address. From what I gather the php script is not ...
8
votes
4answers
27k views

Appending current date to filename

I'm trying to append the current date to the end of a file name like this: TheFile.log.2012-02-11 Here is what I have so far: set today = 'date +%Y' mkdir -p The_Logs & find . -name The_Logs ...
1
vote
2answers
183 views

receiving command as a parameter in bash

I have a following simple script called single-instance that executes the given command if there is no process under that command running. If I hard-code the command after the else statement, it has ...
4
votes
2answers
4k views

Read entire file into memory?

Is there any way to read entire file into memory in bash, without using external command like cat? I know the syntax to get output from a file, i.e <(/bin/ls), but now I need to read the file into ...
2
votes
1answer
205 views

Zsh style arrays with Bash

Does Bash have a way to access arrays similar to Zsh, something like $ foo=(dog cat mouse) $ echo $foo[1] cat instead of $ echo ${foo[1]} perhaps using some shopt setting?
3
votes
3answers
597 views

Rename multiple directories decrementing sequence number?

I have a directory which contains a number of subdirectories with names on the format dir.##. The prefix is always the same, and the suffix is 1-3 digits in a strictly incrementing sequence. Thus, ...