Questions about bash only, as opposed to other Bourne/POSIX shells. For all Bourne/POSIX-style shells, use the /shell tag instead.

learn more… | top users | synonyms

11
votes
5answers
20k views

Is there a way to set the size of the history list in bash to more than 5000 lines?

No matter how much I set the HISTSIZE environment variable to be larger than 5000, when printing the history list with the history builtin, it prints only the last 5000 commands. I need that because I ...
7
votes
1answer
1k views

Customizing bash shell: Bold/color the command

There are a number of tutorials/posts online (e.g. http://www.cyberciti.biz/faq/bash-shell-change-the-color-of-my-shell-prompt-under-linux-or-unix/) about how to customize your prompt in bash by ...
2
votes
1answer
159 views

Need to find a cronjob

I have a problem, some user ,and I'm not sure who, on one of my servers wrote a cronjob that executes every night at midnight. The cronjob creates a sql dump of a database which is then grabbed by ...
95
votes
14answers
134k views

How can I resolve a hostname to an IP address in a Bash script?

What's the most concise way to resolve a hostname to an IP address in a Bash script? I'm using Arch Linux.
5
votes
4answers
1k views

Which stream does Bash write its prompt to?

I am trying to redirect all output from bash (prompt, user input, results) to a file Example: /bin/bash > file.txt 2>&1 I thought that would work, but I'm not getting the prompt. Can ...
5
votes
1answer
779 views

How to stop Bash appending history

I am having a lot of trouble setting up the terminal history of Bash the way I want. I would like to have no duplicate entries and if I enter a command I want it saved and the duplicates above ...
3
votes
1answer
1k views

Load my .profile for bash in Emacs terminal buffer? (multi-term mode)

I've got multi-term mode (derived from ansi-term) with bash started in Emacs 23.3, which is a terminal emulator running in Emacs. However, I noticed that it did not load my user profile, including ...
3
votes
2answers
468 views

Using `select` command to print menu in Linux

I am trying to implement a simple menu using select command. The script (for testing purposes) is as follows #!/bin/bash echo "*******************" PS3='Select an option and press Enter: ' ...
7
votes
1answer
478 views

Note-taking and outlining using Vi: On startup, highlight tags and display tags in a preview window [duplicate]

I am using vi as a note-taking and outlining tool and therefore I thought that this stackexchange site would be appropriate to ask this question. I am constructing the "tags" file by myself. What I ...
0
votes
2answers
192 views

How to put Mysql path in bash profile on MacBook Pro 10.6.8

I want to put a mysql path into the bash profile of my macbook pro. How do I access the bash file and then make it visible in the finder so I can open it with a text editor and put in the path?
1
vote
2answers
707 views

Unix read -p command causes bash error, how do I fix it?

I'm trying to prompt the user for a comment function comment { if [ ! $1 ] then read -p "enter checkin comment < " COMMENT; else export COMMENT="$1" fi if [ ! $COMMENT ] ...
3
votes
3answers
7k views

Is there a way to write a script to do ftp login so I don't have to type things over and over again?

I am recently working extensively with a remote system via ftp connection, since the session time is so short that I have to re-login quite often when I finish my work on my local machine, so I need a ...
5
votes
2answers
1k views

TinyCore Linux & RVM

I'm running TinyCore Linux and when I tried to install RVM (needed a portable linux distro for QA Automation) I keep getting an error sh: syntax error:unexpected redirection. I am unsure why I am ...
8
votes
4answers
6k views

Make cd automatically ls

I find that I often do the following: %> cd bla/bla %> ls I would like it that whenever I cd into a directory it automatically does an ls. I fiddled with my .bashrc for a while, but couldn't ...
3
votes
1answer
340 views

Removing redirection operator does not change output. Why?

I saw this usage of redirection somewhere, and thought it was a typo: grep root < /etc/passwd But after I run it, I saw that it gives the same output with grep root /etc/passwd: $ grep root ...
4
votes
1answer
98 views

Quoting in a function results in error

How should I write the command variable to get the expected behavior? #!/bin/bash function f ( ) { echo "$2" } command="f --option=\"One Two Three\" --another_option=\"Four Five Six\"" $command ...
7
votes
2answers
1k views

How to hinder root from running a script

The Glassfish application server provides scripts to administer the application server and also start and stop them and I would like to restrict the root user from running this script. The reason is ...
4
votes
1answer
2k views

shorthand for feeding contents of multiple files to the stdin of a script

Hi good people of this community, Say I have a script called script, that reads from stdin and spits out some results to the screen. If I wanted to feed it contents of one file, I would have typed: ...
3
votes
3answers
3k views

How can I test if a program is running from within a script

Let's assume that another user started a bunzip process, and I have a script that I'd like to start running after that bunzip finishes. What's the best way to check from inside my script that the ...
5
votes
3answers
2k views

Indirect return of all elements in an array

The Bash man page describes use of ${!a} to return the contents of the variable whose name is the contents of a (a level of indirection). I'd like to know how to return all elements in an array using ...
9
votes
2answers
2k views

Why does a bash here-string add a trailing newline char?

The following examples show that a newline is added to a here-string. Why is this done? xxd -p <<<'a' # output: 610a xxd -p <<<'a ' # output: 610a0a
8
votes
6answers
572 views

How to disable emacs here document completion

When editing a bash script file with emacs, and trying to enter <<<, at the second < emacs insert a template for a here document, like in the following example: <<EOF EOF This is ...
24
votes
7answers
23k views

How to add newlines into variables in bash script

When I do str="Hello World\n===========\n" I get the \n printed out too. How can I have newlines then?
3
votes
2answers
403 views

Why does $((40-35)) turn into 5?

What kind of strange shell syntax is hidden behind $((40-35)) and how come it calculates a value? Example: $> echo $((40-35)) 5
3
votes
1answer
4k views

Compress a directory using tar/gz over SSH to local computer?

I'd like to essentially tar/gz a directory on a remote machine and save the file to my local computer without having to connect back into my local machine from the remote one. Is there a way to do ...
5
votes
2answers
1k views

What do these commands (`tar`) actually do? Is there a better way?

I am going over some documentation pertaining to creating a distro repo. However, I cannot understand exactly what these commands perform: # cd /mnt/ # ls centos-1 centos-2 centos-3 # for i in 1 2 ...
4
votes
2answers
173 views

Why do newlines mess up my while condition?

I have a while loop that allows setting variables when written one way but does not allow it when written another way. Why is that? This prints var as 1234 and does not print var2 #!/bin/bash ...
2
votes
2answers
3k views

Displaying and updating a counter in bash

I think it's something like this: (Fedora14/bash) #!/bin/bash for i in {0..10..1}; do echo -e "$i"'\c' echo -e "\n\r" sleep 1 done But it doesn't work. Purpose: like this, but without the ...
-1
votes
1answer
1k views

Loop examples in bash [closed]

Any examples for "loop" in bash? for i in {1..5}; do echo $i; done 1 2 3 4 5 AND for i in 1 2 3 4 5; do echo "Welcome $i times"; done Welcome 1 times Welcome 2 times Welcome 3 times Welcome 4 ...
3
votes
4answers
1k views

How to run java process to be seen not as 'java…' in processes list?

Is it possible to run a Java process in Linux in a way that it could be seen in ps as some sort of alias? It would be easier to restart it when it is down.
4
votes
4answers
1k views

How can I remove a specific string from a file only if there are other lines in the file?

How can I remove a specific string from a file ONLY if there are other lines in the file? For example, don't touch this file: cat file.txt ASDF but remove "ASDF" from this file: cat file.txt ASDF ...
6
votes
1answer
1k views

All about ssh ProxyCommand

I am looking for an in-depth explanation of the following ProxyCommand, down to the nuts and bolts of its operation, please. Can you kindly completely dissect it for me and improve on it if you can? ...
3
votes
3answers
2k views

executing multiple greps in a single find command

I want to use find command to find some files containing multiple patterns at the same time. I tried something like this: find . -name "*.xml" -exec grep -iH keyword1 + && grep -iH ...
6
votes
5answers
639 views

copy consumed output to stdout when stdout is redirected to a file

Given a command the output of which is being processed by, for example, grep I also want the actual output to be included in the log file for debugging purposes. For example if I have the following ...
3
votes
2answers
770 views

How to use $? and test to check function?

#!/bin/sh function checkExit(){ if test "$?" != "0"; then echo Command $1 exited with abnormal status exit 1; else echo $? fi } function echoThenRun () { # echo and then ...
1
vote
3answers
3k views

Testing if a process is running via if and -z

I'm have a process on my system which is notorious for crashing, and is kind of mission critical, my network manager. In any case, I need to write a loop which tests if it's running and starts it if ...
2
votes
3answers
171 views

How to pass lines from a file to a bash script, so that each line remains undivided, even if there are spaces?

Given: $ cat lines.txt a/b 'c/d e/f' $ cat 1.sh #!/bin/sh ./2.sh `cat lines.txt` $ cat 2.sh #!/bin/sh echo p1=$1 echo p2=$2 echo p3=$3 $ ./1.sh p1=a/b p2='c/d p3=e/f' How do I change lines.txt ...
4
votes
2answers
1k views

What is the “caller” command?

I'm running Ubuntu 10.10 with openbox running on top. I noticed today a command called caller, however there is no man page, it does not respond to any input (or --help) and whereis doesn't find it. ...
2
votes
3answers
579 views

variable concatenation not working?

I have a simple bash shell script which is driving me bonkers. All I want to do is run a command which returns a result which I will then use in another command. The result of the first command ...
6
votes
2answers
774 views

Using bash “double paren” arithmetic expansion, math fails with leading zero

I have a simple script that deals with hours and minutes. If I want to calculate number of minutes since midnight having a string s hh:mm I tried splitting string then doing hh * 60 + mm My problem ...
3
votes
2answers
192 views

filename with no spaces from two command lines

I am running two Linux commands and I want to put the resulting values together in a filename with no spaces and a dot separating the two values. So far, I've got this: pid=`sudo dmidecode -s ...
7
votes
3answers
6k views

Why does the exclamation mark `!` sometimes upset bash?

I realize that ! has special significance on the commandline in the context of the commandline history, but aside from that, in a runing script the exclamation mark can sometimes cause a parsing ...
2
votes
2answers
2k views

Bash color output fails

Is it sed or echo problem? What I'm doing wrong? $> cat ~/bin/color_test.sh #!/bin/bash ColorOff='\e[0m' # Text Reset BWhite='\e[1;37m' # Bold White string="test TEST test" echo -e ...
0
votes
1answer
4k views

How to know how long a process has been running? [duplicate]

Possible Duplicate: How to check how a long a program has been running? I am interested in doing this purely using bash.
4
votes
2answers
12k views

Bash shell script to locate and remove substring within a filename

I am trying to write a bash shell script in Mac OS X 10.6 (which is called by an Automator Action) to rename TV show DVD rips that I have named badly over the years. I want to remove part of the text ...
15
votes
2answers
10k views

bash multi line command with comments after the continuation character

Consider echo \ # this is a comment foo This gives: $ sh foo.sh # this is a comment foo.sh: line 2: foo: command not found After some searching on the web, I found a solution by DigitalRoss on ...
2
votes
2answers
334 views

Bash Script Argument Regex Group Conflict

I have a simple bash script: input_dir="`dirname $1`/`basename $1`/" output_dir="`dirname $2`/`basename $2`/" ext=$3 ... ... ... echo -n `rename "-f" "'s/.*([0-9]{11}_[0-9]{11}).*\.(.*$)/$1.$2/'" ...
9
votes
2answers
358 views

Weird control-d behavior

I can use cat as a very simple text editor by doing cat > foo.txt. If I then type: bar baz and then press ctrl+D, it now looks like this: $ cat > foo.txt bar baz^D with the cursor at the ...
2
votes
4answers
1k views

Why is grep -o -w not giving me the expected output on Mac OS X?

If I do echo foo bar baz | grep -o -w baz the output is foo bar baz (and an extra newline). The expected output would be baz as the -o option should only display the matched part. I'm using Mac OS X ...
20
votes
6answers
24k views

How to replace one char with another in all filenames of the current directories?

How do you rename all files/subdirs in the current folder? Lets say, I have many files and subdirs that are with spaces and I want to replace all the spaces with an underscore. File 1 File 2 File 3 ...