Bash is the shell from the GNU project. It is the standard shell on Linux and often available on other unices. If your question applies to all Bourne/POSIX-style shells, use the /shell tag instead.

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3
votes
3answers
789 views

Why is delay after ifconfig down needed before up if changing MAC address?

Hi I made bash script to put down my interface, change MAC address and get it up again. #!/bin/bash INTERFACE_STATUS=$( cat /sys/class/net/eth0/operstate ) echo "$INTERFACE_STATUS" if [ ...
6
votes
5answers
77 views

SED : Case Match Pattern Replacement

I have a source code spread across several files. It has a pattern abcdef which I need to replace with pqrstuvxyz. The pattern could be Abcdef (Sentence Case) then it needs to be replaced with ...
2
votes
3answers
28 views

How can I use an “alias” for the destination directory when copying?

I frequently edit startup files such as my .bashrc file Then I copy them to another direction such as ~/Dropnot/level1/setups/bash1 Is there any way I can cp such files to the above location with ...
3
votes
2answers
97 views

How can I use nested [] to replace a if-then-fi ? (“[: -f: binary operator expected”)

In my .bashrc file I have: if [ -f /etc/bash_completion ] && ! shopt -oq posix; then . /etc/bash_completion; fi I wanted to use [] around it instead of if then fi I already have [ -f ...
1
vote
0answers
19 views

How do I change the default action of F1 key in an ncurses program? [migrated]

I am using fedora 20 and learning ncurses programming by studying example programs. I have reached one in NCURSES Programming HOWTO (listed below from my file "border.c", see note) that should exit on ...
3
votes
2answers
28 views

How do I break up a file like split to stdout for piping to a command?

I have a large .sql file full of SELECT statements that contain data I want to insert into my SQL Server database. I'm looking for how I could basically take the file's contents, 100 lines at a time, ...
3
votes
2answers
116 views

How can I print out all but the last n characters in bash?

I'm working with standard input (cating two files together) and want all but the last 10 characters of the result to be passed through the next command. All I can find through searching is using sed, ...
4
votes
2answers
71 views

Printing an array to a file with each element of the array in a new line in bash

I am trying the contents of an array into a file with each element of the array in a new line in the file. IFS=$'\n' echo "${mtches[@]}" > sample1.txt The content of mtches is "qwe" and " ...
3
votes
0answers
29 views

Proper usage of EXIT & ERR traps in bash scripts

I'm working on a bash script and as I've been going I've learned about traps, signals, function return codes and other such features I've not previously used. I may be thinking about things ...
0
votes
0answers
3 views

udev set kdbrate settings on linux with console users issue

I have a kbdrate setting as a udev rule for usb devices(keyboards and scanners that re repluggd in). kdbrate needs to be set by someone with /dev/port access which is the console user. The udev rule ...
9
votes
4answers
911 views

How can I find a rogue alias declaration?

I'm trying to find where a specific alias has been declared. I've searched all the usual places I know to look for aliases: ~/.bashrc ~/.bash_profile /etc/bashrc /etc/profile With no luck. I know ...
3
votes
1answer
31 views

Piping commands, modify stdin write to stdout

echo Hello World | nano - | less I want to modify Hello -> Goodbye while in the the text editor. It does not have to be with nano. I am stuck with nano reading stdin but requiring me to write to a ...
5
votes
3answers
438 views

Run ssh login command without modifying remote .bashrc

We have a bunch of servers set up with set -o vi in their ~/.bashrc. It would be nice to be able to ssh into these boxes and automagically run set -o emacs as a timesave. I've seen a solution ...
0
votes
2answers
39 views

Finding an elements in an array in bash

I am using the following code to first split an array into 2 and then search if 2 elements "Alchemist" and "Axe" are present in each of the two split arrays. tempifs=$IFS IFS=, match=($i) ...
5
votes
1answer
47 views

Save password in bash script for multiple queries

I would like to know if there is a safe way to only be queried for a password once in a custom bash script, and then save it somehow to be used for later needs. At the end of the script it should be ...
6
votes
4answers
477 views

Combined `mkdir` and `cd`? [duplicate]

is there any way (what is the easiest way in bash) to combine the following: mkdir foo cd foo The manpage for mkdir does not describe anything like that, maybe there is a fancy version of mkdir? I ...
27
votes
6answers
17k views

Why doesn't my Bash script recognize aliases?

In my ~/.bashrc file reside two definitions: commandA, which is an alias to a longer path commandB, which is an alias to a Bash script I want to process the same file with these two commands, so I ...
4
votes
3answers
94 views

Dynamically trim stdout line width in Bash

Lately, I have been experimenting with the ps command, and sometimes long paths wrap to the next line (or two) and make it hard to read. I want to pipe the ps output into another program to limit the ...
14
votes
2answers
303 views

bash_history: comment out dangerous commands: `#`

To prevent logging "dangerous" commands in bash history, I have added following line to my .bashrc file: HISTIGNORE='rm *:mv *:cp *:cat*>*:pv*>*' this works well, but it has a side effect: I ...
0
votes
1answer
24 views

understand the output of stty -a and change ctril backspace to just backspace

I am working in bash shell on a Solaris environment and whenever I type "backspace" it clears out the entire line. Do you have any suggestions for me to change the backspace clearing entire line to ...
2
votes
3answers
41 views

How to do more than one substring replace at once in bash?

I have a directory contains image files that are to be echoed in bash. While echoing, I want to replace both file name and extension in single line command. Example files: images/file_name_1.jpg ...
1
vote
2answers
260 views

Augeas in shell script

I'm trying to use augtool in shell script ex: #!/bin/bash augtool <<-EOF print /augeas/load EOF However if I execute this script, the script will run indefinitely with no output and the CPU ...
12
votes
5answers
347 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 ...
2
votes
1answer
20 views

Get bash DEBUG trap to execute only once for and/or lists?

Suppose I set a trap on DEBUG like so: unset PROMPT_COMMAND # don't want $PROMPT_COMMAND triggering DEBUG trap trap 'printf %s\\n "most recent history line: $(history 1)" >&2' DEBUG If I do ...
3
votes
2answers
3k views

Bash script that automatically kills processes when CPU/memory usage gets too high

I have created a script that kills processes if CPU and/or memory usage hits 80%. It creates a list of killed processes when this happens. What can I do to improve it? while [ 1 ]; do echo echo ...
2
votes
2answers
54 views

PS1 variable no longer shows coloured bash prompt

I'm running a VPS with Centos 6.5 I've setup ~/.bash_profile as in the following screenshot: It used to give me an output like this: Now that I've installed WHM/Cpanel I no longer see coloured ...
-4
votes
1answer
41 views

-bash: -sudo: command not found [on hold]

Some dependencies were missing when I installed THC Hydra. I found this site: http://www.aldeid.com/wiki/Thc-hydra which directed me to install the missing package via this line code: sudo apt-get ...
4
votes
5answers
99 views

`ls -l` of a file and all the directories leading to it?

Before I start writing a (probably easy) script, is there a command that does the equivalent of the following one: [:~/software/scripts] % ls -ld / /usr /usr/bin /usr/bin/tee drwxr-xr-x 21 root root ...
2
votes
3answers
51 views

Compare two files for matching lines and store positive results [duplicate]

I have two files. File 1: A0001 C001 B0003 C896 A0024 C234 . B1542 C231 . upto 28412 such lines File 2: A0001 A0024 B1542 . . and 12000 such lines. I want to compare File 2 against File 1 ...
2
votes
2answers
17 views

Capture transcript of program with redirected input and output

A typical interaction for a program I've written might look like this: Enter command: a_command Completed a command Enter command: another_command Completed another command I typically run my ...
0
votes
2answers
41 views

ln -s with a path relative to pwd

I'm trying to create a bunch of symbolic links, but I can't figure out why this is working ln -s /Users/niels/something/foo ~/bin/foo_link while this cd /Users/niels/something ln -s foo ...
1
vote
3answers
28 views

Shell vi mode prints (arg: repetition): How to remove it?

Whenever you are in vi command mode on the shell and hit a number, like 8, "(arg: 8)" shows at the start of the line. Anyone know how to make it not do that? The moving the line I'm typing is ...
0
votes
3answers
427 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} ...
6
votes
2answers
982 views

what will ¬ do in bash?

While wanting to start gitg as backgrounded through writing gitg & I accidentally typed gitg ¬. This did not cause an error, instead I got with a later command in the same terminal (translated): ...
5
votes
2answers
156 views

How process substitution is implemented in bash?

I was researching the other question, when I realized I don't understand what's happening under the hood, what are those /dev/fd/* files and how come child processes can open them.
7
votes
6answers
602 views

Is it possible to remove folder prefix from a `ls` command

I am in a bash script and I want to get the list of all files (let say all jar files). I execute the command ls -1 lib/*.jar and I get the output: lib/mylib_1.jar lib/mylib_2.jar ... Is there any ...
4
votes
2answers
111 views

Process substitution from curl to bash as root

I'm trying to run a script from URL as root with this command: sudo bash <(curl -s http://copy.com/gLVZIqUubzcS/popcorn) But I'm getting this error: bash: /dev/fd/63: Aucun fichier ou dossier ...
5
votes
0answers
93 views
+50

Bash completion for comma-separated values

I would like to create completion rule for comma-separated parameters list. E.g. I have command which receives list of server names: myscript -s name1,name2,name3 At this moment I've managed to ...
2
votes
2answers
34 views

Is it possible to generate a separate file list when creating a tarball?

When using tar for backups I'd like to create a separate list of the files that is included in the archive for storing alongside the backup tarball. Solutions that's not so good: tar --verbose ... ...
4
votes
2answers
448 views

What does tail -f <directory name> do?

I mistakenly executed the following command in the terminal: tail -f /logs/applications/logs* I got the following output: tail: file shrunk! Error 0 I am not sure what exactly happened. I have ...
2
votes
2answers
268 views

How to open process substituted file from php?

Here's what I tried to do myself: $ type 1.sh #!/bin/bash -eu php -r 'var_dump(file_get_contents($_SERVER["argv"][1]));' -- <(echo 1) $ ./1.sh PHP Warning: file_get_contents(/dev/fd/63): failed ...
3
votes
1answer
35 views

Customize bash to always include a certain parameter

When using the "ls" command, bash prints in the following format: file1 file2 file3 file4 file5 file6 file7 file8 But when given the parameter "-1", it prints: file1 file2 file3 etc... Is there ...
0
votes
1answer
671 views

How to change terminal character encoding

Today I uninstalled the GUI packages on my home CentOS installation. Now, when the machine starts, I get the login prompt. It acts finicky. Sometimes pressing enter just once after answering each ...
5
votes
3answers
399 views

What is the difference having double quotes or not in bash [duplicate]

I have some bash scripts, one which has the following content: #!/bin/bash source $(dirname ${BASH_SOURCE[0]})/script.sh while the other one has the following content: #!/bin/bash source ...
4
votes
2answers
53 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 > ...
0
votes
2answers
71 views

How do I run a command on a TTY from a SSH session?

Does anyone know of a way that I could run a command from my ssh session and have it display on tty1? It seems like I could do that like: script command >> /dev/tty1. However, if I were to do ...
8
votes
4answers
1k views

Displaying week's number in certain format using ncal or cal

Don't you just love it when two commands each do one thing you want but neither do both? This is what cal does. Nice formatting. Lacks week numbers though. $ cal January 2012 Su Mo Tu We ...
4
votes
3answers
192 views

What are the color codes that I can use in my PS1 prompt?

I used several colors in my PS1 prompt such as \033]01;31\] # pink \033]00m\] # white \033]01;36\] # bold green \033]02;36\] # green \033]01;34\] # blue \033]01;33\] # bold yellow Where can I ...
2
votes
1answer
349 views

Gnome + Linux: GUI apps don't inherit PATH from parent console apps

In Gnome, don't GUI applications inherit the PATH of the shell process that launches them? Apparently, GUI applications see only the PATH specified in ~/.profile. No issues with console applications, ...
3
votes
1answer
51 views

compgen warning: -C option not working as I expected

What is the correct way to use the compgen -C option? I'm trying to learn about Bash programmable completion, and in particular the compgen builtin function. I'm experimenting with the different ...