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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2
votes
2answers
33 views

brace expansion and * expansion

Assume in the working directory, there is only one djvu file. I would like to backup the file into a file with file name having extra .bk at the end. cp *.djvu{,.bk} copies the djvu file into a file ...
0
votes
0answers
10 views

Datum in a CSV file to pushed/sent over to Google Charts

I have a CSV file, where the accumulated data is as such (just a snippet): ... 20150327,TEST-MACHINE-091,9,10 20150327,TEST-MACHINE-092,2,7 20150327,TEST-MACHINE-093,1,4 ...
5
votes
1answer
115 views

In which situations are PS2, PS3, PS4 used as the prompt?

When I log on into the shell I see the prompt whose value is stored in PS1. I also encountereded another prompt (but do not know which one) when I used the here-document syntax: bc << HERE ...
0
votes
1answer
36 views

Shell script to compare two tables and perform operations on their columns

I have two tables like the following: Table 1 TABLE_NAME COUNT ------------------------------ ------------ AIN_EDP_SCRIPT 33 AMA_CALLTYPE_LOOKUP ...
0
votes
1answer
32 views

Modify part of line if keyword is found using sed? [duplicate]

I want to modify a line if a specific keyword is found in a line. CS_CODE, SM_NUM, PORT_NUM, DEV_PORT_NUM, DIRNUM, MAIN_DIRNUM, BILL_NO, ADR_NAME In above line, if 'PORT_NUM' is present then ...
0
votes
3answers
32 views

grep log lines of a specific id request

So, I have the following log sample: 2015-03-30 10:19:44,200 DEBUG [Default : 1] [Application:ABC BIW: IDA:6d87de8e-1276-4496-b49d-dd4cd375cbe4 Info:P23 Code:ABCD] A log message 1 2015-03-30 ...
2
votes
1answer
24 views

Need to press enter to get prompt after executing udev script

I have set a simple udev rule for my Raspberry Pi (Debian) to automatically mount an USB HDD. It just runs a script which mounts all devices in /etc/fstab since it's the only one I have and I'm going ...
1
vote
0answers
34 views

bash scripting : using expect

I am facing an issue when I run simply these commands. The remote server want to pass "yes" to add the key in RSA file because first time connection established with scp. commands are given below ...
2
votes
0answers
31 views

Bash: “history number” vs “command number”

While Googling how to customize my shell prompt via the PS1 variable, I'm seeing tables of special characters that can be used. In particular: \! the history number of this command ...
0
votes
1answer
28 views

bash script taking input [on hold]

I have written a bash script. It is launched like this: ./myscript.sh $IP COMMAND-FILE In COMMAND-FILE I give commands which I have to run on remote server. But now I have to use another script in ...
0
votes
0answers
44 views

Incremental search [on hold]

How to enable incremental command-history search in terminal, for all users, in debian? I have to edit the /etc/bash.bashrc right? I am refering to this: ...
1
vote
2answers
42 views

Parsing C Style Multiline Comment

I want to filter non-commented javascript with sed and output the line number Here is the example: /*! * jQuery UI 1.8.17 * * Copyright 2011, AUTHORS.txt (http://jqueryui.com/about) * Dual ...
1
vote
1answer
29 views

How to use convert command with bash to resize all images in a given directory?

I want to resize all PNG files in ~/somefolder/ whose filenames are NOT started with tn_ to 50% of its original size and rename the output file with a tn_ as its prefix and its original name. I know ...
1
vote
1answer
31 views

awk script to rearrange similar rows

I want rearrange about 5 million rows (with 300 columns) into groups. Data looks like the following: where there were various experiments (column 2) conducted at different locations (column headers ...
2
votes
1answer
25 views

How do I run two processes and find out when one ends in bash

I was thinking to do something like this: command1 & command2 wait Will this work? I want to proceed when command2 finishes, but command1 can still be running.
1
vote
1answer
27 views

How can I detect that not enough options were passed with getopts

I want to add a line of code that tells the user that enough arguments were not given (may be an error message somewhere. but i am not sure where?) blastfile= comparefile= referencegenome= ...
1
vote
1answer
20 views

Write output from netcat to a file

I'm currently trying to write a scan port result to a text file Here is the command I tried to use: nc -vv -z localhost 1-80 > file.txt This doesn't work (that is, the error messages from nc ...
2
votes
3answers
159 views

Double square brackets for FreeBSD

I have this code: [[ "$1" =~ [/\\]$ ]] On linux it works just fine, but when I tested it on FreeBSD an error occured : ./projekt2.sh: [[: not found and it .. I there any alternative which would ...
2
votes
4answers
117 views

How can I create new shell commands?

I'm using bash, and I want to be able to execute a script just by typing its name as a command, same as pwd for example. Is there a specific directory where I need to save my script to, or any other ...
0
votes
1answer
41 views

Syntax Error: unexpected end of file — Bash script [on hold]

I am trying to create an spritz app. Everything was working fine, but since yesterday I keep getting this error: ./spritz: line 176: syntax error: unexpected end of file I have checked the script ...
-1
votes
2answers
20 views

Create new file with spaces from argument BASH [duplicate]

I need to create new file which contains spaces in it. And it is passed through the argument. This code below creates 2 sepate files. Can anyone help me how to create 1 file which will contains space? ...
2
votes
0answers
22 views

Catch/diagnose user process being killed - Inexplicably logged out automatically

Context: I'm using bash in Mac OSX Yosemite. Problem: I'm executing a (python) script that I expect to use alot of resources and take a few hours to run, redirecting stdout and stderr to a log file. ...
-1
votes
1answer
11 views

Syntax Error: unexpected end of file — Bash script [duplicate]

I am trying to create an spritz app! Everything was working fine, but since yesterday I keep getting this error: ./spritz: line 176: syntax error: unexpected end of file I have checked the script ...
2
votes
2answers
35 views

How to set Timeout for an ssh command and also get back the result of remote commands

I have a script that runs on bash, in an RHEL server that connects to thousands of nodes and returns with the values of some 5 executed commands - It collects info from RHEL Servers only. It works ...
4
votes
2answers
177 views

Convert all first character in an email id to Upper case in BASH

I need to accept an email id and Full name in a script, and in case the Full name is not provided, I need to generate the name from the email id. Something like this: Case 1: EmailID: ...
0
votes
1answer
31 views

how to count the length of an array defined in bash?

I'm new to bash and can't find a good tutorial to answer my question. array=( item1 item2 item3) for name in ${array[@]}; do echo current/total ... some other codes done I want to calculate ...
-4
votes
0answers
15 views

BASH— after getopts continues after exit [on hold]

in getopts(probably) it has two functions in it. One of them has exit at the end and there is also exit at the end of the option b. When I call it like this: ./name.sh -b. (without required argument) ...
3
votes
1answer
16 views

vipe misbehaving on bash process substitution

I have the following simple command: $ echo <(vipe) I expected it to open a vim buffer, which I can edit, then when I'm done, echo the name of the temporary file assigned to hold the vim buffer ...
3
votes
1answer
24 views

Moving sub-directory to new parent directory where the new directory name is incremented by 1

I am attempting to move a sub-directory from one parent directory to another for hundreds of instances, while changing the name of the sub-directory during the move. My directories are a set of ...
2
votes
1answer
45 views

what are practical uses of stdbuf or nohup?

I have to finish a writeup of a few coreutils commands for a course at the moment, and I can't think of a starting point for a small practical code example that demonstrates the potential uses of ...
0
votes
1answer
47 views

What does $'text' do exactly in Bash? Can it be used in Zsh?

I recently run into the following proposed solution: cat results.csv | tr $'\x01' \\t > result.csv to convert a malformed csv file (one that uses \x01 unicode as a separator) into a correct one. ...
0
votes
1answer
49 views

Why are my variables not reset to zero?

In the below loop, I try to reset the values of two variables (totalentries and totalusedbytes) to zero, but I can see from the results that it never happens. Thus each loop continues to add to the ...
0
votes
1answer
44 views

Shell— print only certain lines from output

I need to choose from output only lines where number is bigger than chosen number. For example x=27 and I need to find only lines where the number in first column is bigger than that x. In this ...
2
votes
1answer
24 views

Removing line numbers from `od`'s output

Is there any flag to od to make it not output line numbers in the result?
-2
votes
0answers
38 views

Combine lines of file to string [duplicate]

I am trying to have a file inputted by my script and put into a string to be put into another file. ./script.sh -u uuids.txt -s servers.txt Each file will have a list with each value being on it's ...
2
votes
1answer
71 views

bash: how to save state on prompt evaluation [duplicate]

I want to put duration of last running command in command prompt, f.ex: user@host$ sleep 360 6m user@host$ Also, I want duration to not show up if it is less than some minimum threshold (say 30 ...
-2
votes
3answers
35 views

Syntax error when trying to cut part of a variable

If I write a simple echo $i, I have no problem: it shows me the variable. But if I try do something with it $($i|cut -d"." -f1-3) then I get an error messages : -bash: /...file.backup: Permission ...
0
votes
3answers
59 views

How to make backticks accept variables as variables?

This is my code: #!/bin/bash machine_we_are_looking_for=$1 user_defined_new_machine_location=$2 condition_while_one=true condition_while_two=true echo "test 1" while $condition_while_one do ...
0
votes
1answer
72 views

Temporary file BASH

does this piece of code creates temporary file? Because I am not supposed to use them and I only found out yesterday that even sed -i creates it. So I can be sure. Thanks while read line; do if [[ ...
1
vote
0answers
37 views

Bash script to get the result from rsync transfer and zip it as a directory in the original directory

OK, I guess this is weird. I have a small stage.sh script very simply has a bunch of commands: if [ "$(whoami)" == 'David' ]; then rsync -a --delete-excluded --exclude-from=.stage_rsync_rules ...
2
votes
2answers
21 views

Can someone explain exactly what is happening with single quotes and double quotes with process IDs in the below example? [duplicate]

[root@localhost ~]# echo $$ 16991 [root@localhost ~]# bash -c "echo $$" 16991 [root@localhost ~]# bash -c "echo $$" 16991 [root@localhost ~]# bash -c 'echo $$' 21062 [root@localhost ~]# bash -c 'echo ...
2
votes
2answers
82 views

How to remove duplicate files using bash

I have a folder with duplicate (by md5sum (md5 on a Mac)) files, and I want to have a cron job scheduled to remove any found. However, I'm stuck on how to do this. What I have so far: md5 -r * | ...
1
vote
1answer
47 views

Why are files and directories colored in different ways? [duplicate]

On Ubuntu 14.04, in bash under gnome terminal, Why are files especially directories colored in different ways? The green colors hide the text to me (How about to you?). Is it done by terminal or ...
0
votes
0answers
26 views

Would this command delete only the lines containing specific words within a delimited area? [duplicate]

Please see my previous question here. No one seems to be following up on it, so I have tried to have a go myself: sed '1 { /^---/ { :a N; /\n---/! ba; /^Title: \|^Place: /d} }' filename Would this ...
20
votes
7answers
1k views

`command .*` acts on the parent directory

Someone of our team wanted to recursively change the user permissions on all hidden directories in a users home directory. To do so he executed the following command: cd /home/username chown -R ...
0
votes
0answers
60 views

Combine lines of file to string [closed]

I am trying to have a file inputted by my script and put into a string to be put into another file. ./script.sh -u uuids.txt -s servers.txt Each file will have a list with each value being on it's ...
0
votes
0answers
54 views

Replace a string with another string in a text file [closed]

I want to replace a string that is in the file file1 with another string. I tried sed -i -e "s/chaines1/chaine2/g" file1 but the problem is I can't pass the two strings on the command line ...
2
votes
3answers
55 views

What happens if I pass too few parameters to a shell function?

I would like to ask about passing parameters into functions. I tried this: function_name $var1 $var2 but usually (sometimes it printed error) it didn't make any difference whether I passed them or ...
2
votes
1answer
38 views

Can I re-login a disconnected session? [duplicate]

For some network reasons, my previous SSH sessions to server have disconnected. When I create a new session, I find the previous session still exist: [root@localhost ~]# who root pts/0 ...
3
votes
1answer
50 views

how to send output of curl request to 2 separate commands

I'm piping the output of a curl request to gawk so that I can pull some data. The gawk code is already working if I'm searching through the html file which curl request produces. However, I was ...