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
1answer
25 views

Is using shorthand quick substitution of history expansion problematic?

In my terminal (bash 3), I sometimes use the quick substitution ^aa^bb^ ^string1^string2^ Quick substitution. Repeat the last command, replacing string1 with string2. Equivalent to ...
1
vote
1answer
19 views

X11 Issues running with Terminal.app

I am trying to figure out why I can't use ghostscript or ghostview (or any other X11 applications) when I try to call them in the Terminal. I am using bash, and I also used Fink to get the packages I ...
2
votes
3answers
66 views

moving a (file | directory) while avoiding filename collisions

I have a bash script that moves files from a number of different locations to a folder named completed. I want to avoid overwriting previous files, so in the case when the name of a file (for ...
0
votes
1answer
17 views

For a given directory, how do I concatenate the tail end of recently modified files to a new file?

In case there's a better solution to the problem, my goal is to be able to quickly analyze ALL recent apache activity in /usr/local/apache/domlogs. The usefulness of this is when the server load is ...
8
votes
3answers
14k views

How do I count the number of occurrences of a word in a text file with the command line?

I have a large JSON file that is on one line, and I want to use the command line to be able to count the number of occurrences of a word in the file. How can I do that?
-1
votes
0answers
35 views

How to I create a file with a sorted list from users that have mail

I need to create a file ~/you have mail, it needs to contain a sorted list of all users on my local system which currently have mail in their "Inboxes" (i.n., their spool of delivered but no yet read ...
1
vote
1answer
263 views

How to see interactive output when running nmap from a bash script?

I'm trying to run nmap from a Bash script, in a way so that when Enter is pressed it should give some output, as happens when running directly from the commandline. When calling a few different nmap ...
14
votes
1answer
735 views

How can I `alias sudo !!`?

I'm trying to set an alias for sudo !! in Bash. I tried alias sbb='sudo !!', but it interprets that as a literal !! and prints sudo: !!: command not found If I use double quotes, it substitutes ...
5
votes
2answers
218 views

Why does !! inside an alias not work?

I have this alias set in my system /etc/bashrc file: alias root="sudo !!" The intention of this being to run the last used command using sudo of course. When used, it of course appears to ...
1
vote
2answers
127 views

Chown permission denied on owned dir

I have following directory (/usr/local) rwxr-xr-x. 43 root root 4096 Jul 25 14:19 . rwxr-xr-x. 14 root root 4096 Feb 21 10:27 .. rwxr-xr-x. 2 root root 4096 Jun 28 2011 bin [...] rwxr-xr-x 1 ...
1
vote
0answers
22 views

Using X11 Displays through Terminal.app commands : generic mapping tools

I am trying to figure out why I can't use ghostscript or ghostview (or any other X11 applications) when I try to call them in the Terminal. I am using bash, and I also used Fink to get the packages I ...
12
votes
5answers
4k views

How can I get bash to exit on backtick failure in a similar way to pipefail?

So I like to harden my bash scripts wherever I can (and when not able to delegate to a language like Python/Ruby) to ensure errors do not go uncaught. In that vein I have a strict.sh, which contains ...
2
votes
3answers
103 views

Count files in a directory by extension

For the purpose of testing, I'd like count how many images files are inside a directory, separating each image file type by file extension (jpg="yes". This because later it will be useful for another ...
2
votes
1answer
55 views

Forward SIGTERM to child in Bash

I have a Bash script, which looks similar to this: #!/bin/bash echo "Doing some initial work...."; /bin/start/main/server --nodaemon Now if the bash shell running the script receives a SIGTERM ...
1
vote
1answer
31 views

processing multiple extensions

I have done a script to convert recursive .jpg files to another size: echo $re mkdir "$re"_tmp for a in *.jpg ; do convert "$a" -resize $re "$re""_tmp/${a%.*} ["$re"].jpg" ; done I'd like integrate ...
0
votes
2answers
35 views

How to list similar lines?

The delimiters could be: " "; "_" INPUT: foo#foo_ehh113#The password of user 111 will expire within the next seven d foo#foo_ehh204#The password of user 111 will expire within the next seven d ...
1
vote
3answers
59 views

Creating an alias for a bash script

So I have tried experimented and created an alias in .bashrc. However, when I test out the command I get: [rkahil@netmon3 ~]$ menu -bash: menu: command not found Here is what I have in the .bashrc ...
2
votes
1answer
38 views

Ctrl-R style interactive search in custom file

I want to be able to search a custom text file similar to the interactive history search in bash. Once the wanted entry is found, executes the line. Bonus Points: have each record contain two ...
3
votes
3answers
79 views

why bash increment: `n=0;((n++));` return error? [duplicate]

n=0; ((n++));echo "ret=$?;n=$n;" ((n++));echo "ret=$?;n=$n;" ((n++));echo "ret=$?;n=$n;" from n=1 on, ((n++)) works correctly, only when n=0, ((n++)) return error, and I am using a trap '' ERR that ...
10
votes
5answers
14k views

How to stop the loop bash script in terminal?

For example, #!/bin/bash while : do sl done How to terminate this bash script?
3
votes
3answers
53 views

Is it possible to have a bashrc for a usergroup?

Is it possible to execute some bashrc file for all users in a group? If you can do that system-wide in /etc/profile then why not for a usergroup?
1
vote
1answer
65 views

Resolve nested aliases to their source commands

I've made several aliases for my convenience.But now I need to be helpful by sending a useful command and it is full of aliases.I've tried doing type u but all it returns is up && ap upgrade ...
2
votes
1answer
44 views

How can I make mailx inform me of new mail?

I'm trying to set up mailx on my server. On one server (Raspbian) I am informed of new mail with a message You have new mail (or something similar). On another machine (Raspbmc), I never have this ...
2
votes
2answers
53 views

Meaning of backslash

Why the following command prints Smith but not \Smith? echo \Smith
2
votes
2answers
72 views

How to write a function in bash?

I am drawing blank here. How should I have written this script? #!/bin/sh XZY_NODES="\ vl-ocnt-1 \ vl-ocnt-2 \ vl-onet-1 \ vl-onet-2 \ vl-ocmp-1 \ vl-oomp-2 \ " is_xyz_node () { host=$1 ...
4
votes
1answer
118 views

Proper way to distribute shell scripts

What is the most proper way to distribute shell scripts, if behaviours of shells can be modified by set and thus are unpredictable? For example, rm *.txt wouldn't be executed as expected on the ...
14
votes
3answers
832 views

Where is bash's history stored?

If I run history, I can see my latest executed commands. But if I do tail -f $HISTFILE or tail -f ~/.bash_history, they do not get listed. Does the file get locked, is there a temporary location or ...
4
votes
4answers
153 views

Indirection on a Bash array

Is there a possibility to write the following script without the loop? IPv4_first=1.1.1.1 IPv4_second=2.2.2.2 IPv4_third=3.3.3.3 IPv4_all=() for var in ${!IPv4_@} do IPv4_all+=(${!var}) done ...
-1
votes
0answers
56 views

Unique id for combination of Latitude - Longitude

I have a LibreOffice Calc table containing one column with latitude and one with longitude. What I want to do is for every unique combination of latitude and longitude a unique number to be assigned ...
14
votes
4answers
3k views

how to download a file using just bash and nothing else (no curl, wget, perl, etc.)

I have a minimal headless *nix which does not have any command line utilities for downloading files (e.g. no curl, wget, etc). I only have bash. How can I download a file? Ideally, I would like a ...
2
votes
2answers
86 views

How to clear the input in Bash

I have a bash script that is reading quite a bit of data /dev/random. I need the user to type randomly to seed the random daemon. However once the script completes everything typed will get dumped to ...
1
vote
3answers
6k views

Yum update problems on CentOS 6.5 minimal as VMware guest

INFO: I am using Windows 7 Pro (64bit) with VMware Workstation version 10.0.1 . I am using CentOS(64bit) 6.5 minimal, for the first time. I am running this from my workplace network, which may use a ...
1
vote
1answer
24 views

dialog --inputbox

Follow the below script I've a unique variable that keeps all variables, I need have each variable separated from $VALUES: #!/bin/bash shell="" groups="" user="" home="" exec 3>&1 ...
5
votes
2answers
77 views

“command | less” vs “less <(command)”

A common "idiom" for viewing large amounts of command output is to pipe it to less, via command | less. However, it's also possible (perhaps only in bash, haven't tested in other shells) to use the ...
2
votes
1answer
58 views

Memory buffer in a bash script

I have recently finished a script that will ask for a hostname and automatically take the argument of the function and ssh into one of my work servers. Here is a copy of my script: #!/bin/bash echo ...
7
votes
4answers
247 views

How can I suppress the space between generated arguments during brace expansion?

I used the following command to create a list of URLs that I want to test: echo -e ...
7
votes
2answers
452 views

Why is `tac file | grep foo' (piping) faster than `grep foo < <(tac file)' (process substitution)?

This question was motivated by "Reverse grepping", about grepping a huge file from bottom up. @chaos said: tac file | grep whatever Or a bit more effective: grep whatever < <(tac file) ...
3
votes
0answers
19 views

Errtrace and local

I am using the following script: #!/bin/bash -Eu trap 'echo Hi' ERR exit_failure() { echo "Hello, World!" return 1 } sub_failure() { res=$(exit_failure) } sub_failure It results in the ...
3
votes
2answers
45 views

bash 'nounset' on sub-shell/child doesn't force main script to exit, how to workaround that globally?

With this script: tstNounset.sh #!/bin/bash set -x set -o nounset;set -u echo `echo $str` function FUNC1() { echo $str; };export -f FUNC1;bash -c FUNC1 function FUNC2() { set -u;echo $str; };export ...
0
votes
0answers
34 views

bash script loses readonly value after first time thru loop

I have a bash script which seems to lose the value of the readonly constant after the first time thru the for-in loop. For example: #!/bin/bash readonly DIR="./groups/" for output in "${array[@]}" do ...
6
votes
3answers
2k views

Bash won't execute files

I have a foo.sh file in my current directory. If I try to run ./foo.sh, I get: -bash: ./foo.sh: /bin/sh: bad interpreter: Permission denied But if I run /bin/sh ./foo.sh then it runs fine. How can ...
1
vote
0answers
53 views

Can I change uuid for network interface in ifcfg-eth* using uuidgen?

I'm creating a script which configuration the network interfaces. The script which generates /etc/udev/rules.d/70-persistent-net.rules and names interfaces to my preference. In CentOS 6.5, my ...
0
votes
1answer
45 views

Test firefox in a loop

I would like to simply bash the following: start firefox, test it, kill its process if it does not work and restart it; or stop the script once for all if it works. Actually I need a awk sentence to ...
7
votes
1answer
241 views

Suse 11 vs. Suse 10 difference impacting terminal colors?

I have my dotfiles versioned on github (shameless fork of other people's fine work). At work, I have them on a central linux server (SuSE Enterprise Linux 10). I rsync them from a central management ...
94
votes
4answers
154k views

How to correctly add a path to PATH?

I'm wondering where a new path has to be added to PATH environment variable. I know this is accomplished editing .bash_rc (for example), but it's not clear how to do this. This way: export ...
0
votes
1answer
47 views

how do I recursivley grep (or otherwise search for) hex strings

Long and short I'm trying to track down some files left by evil scum on a server. fgrep -r "STRING" /path/here has been working well for finding general stuff. However, how do I search for hex ...
8
votes
3answers
434 views

Creating a Bash script that will execute a program and if it exits without crashing, will run it again

I'd like to know the easiest way of creating a bash script that will run an app in MacOSX (it's a UNIX based system so I assumed this was the right place). wait for the program to exit. If the exit ...
1
vote
4answers
705 views

how to replace a value with a calculation in bash/sed

I used bash sed to replace ip address in a group of files, i.e 10.1.1.x => 10.2.2.x-19: file1: 10.1.1.29 => 10.2.2.10, file2: 10.1.1.30 => 10.2.2.11, file3: 10.1.1.31 => 10.2.2.12, ...
3
votes
1answer
46 views

How do I stop a bash shell PS1 color to stop at the end of the command?

So simple question really, I have a custom PS1 colour where I have the actual shell commands in a distinct colour, just so I can quickly see what commands I typed and separate it from the command ...
1
vote
0answers
15 views

Mirrored Linux Commands [duplicate]

I've encountered two incidents where commands (or logic flow) is given forward and backwards In bash scripts: if ... fi (use to closed an if-statement) and in GNU/Linux command line: cat; tac (cat ...