The shell is unix's command-line interface. You can type commands in a shell interactively, or write scripts to automate tasks. Use this tag for questions applying to /bin/sh and most compatible shells (ash, bash, ksh, zsh, …).

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2answers
115 views

Piping commands together in unix

How do I pipe the output of one command to another in unix? For example, If I want to pipe the output of sort to tail, how would I do that?
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3answers
993 views

Shell script Variable Structure

How can I create a variable with a file name format like : FileName pattern: SnapshotIR__somenumber.csv I tried something like : TODAY=$(date +"%m%d%Y") SNAPSHOT = $(SnapshotIR$TODAY*.csv) I ...
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3answers
4k views

Create symbolic links to files using wildcards

I want to create symlinks to multiple files: ln -s dev-*.php 's/dev-(.*\.php)/$1/' Results hoped for: site.php links to dev-site.php file.php links to dev-file.php What's the most ...
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2answers
1k views

Get the complement of the result of an ls command

Let's say I have a directory with multiple files, all of which are either binary files (files with no declared extensions) and source files (.c extension). I do this: $ ls and get: README.md ...
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3answers
3k views

Extract the base file name from a URL using bash

url=http://www.foo.bar/file.ext; echo ${url##/*} I expected this code to print file.ext, but it prints the whole URL. Why? How can I extract the file name?
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1answer
834 views

Send email if specified files do not exist

I am new to unix scripting. I have to do something like : In a folder /x everyday 10Pm and next day 3 AM, 2 files are placed. I have to write a script which will check the folder /x and confirm if ...
1
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2answers
121 views

Cron creates vim process but does not display vim

Under MacOSX 10.8.2 I am able to run vim as follows in the bash shell: /usr/bin/vim -c "normal G" -c 'startinsert' ~/.journal If I put the exact same command in a script: #! /bin/bash export ...
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0answers
198 views

(KDE or X ) Script opens konsole in wrong virtual desktop

I have this script. I put it in ~/Desktop. I view the script on my desktop in a "Folder View" widget. When I click on the script, I get list of users, then I get an authorization dialog box ( for a ...
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1answer
3k views

How to match 2 large file and print the difference in shell script

I have 2 files. File1 has 400k numerical records. e.g: 1 2 3 4 5 6 .. and so on File 2 also has 420k numerical records. e.g: 1 2 3 4 6 .. and so on Both these file are in unsorted manner. I want ...
3
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8answers
4k views

grepping dotfiles with -R correctly?

From time to time I need to find a culprit in an unknown dotfile and instead of trying to figure out which package is to be blamed (e.g. xfce4 or thunar?) and what is their naming convention (.app vs ....
2
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1answer
2k views

How does wc -l `ls` give the actual number of lines?

Can anyone explain to me how does this command work. wc -l `ls` while this command gives the total number of java lines or txt lines.
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1answer
10k views

how to compare two xml files having same data in different lines?

I have two files have same data but in different lines. File 1: <Identities> <Identity> <Id>048206031415072010Comcast.USR8JR</Id> <UID>ccp_test_79&...
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2answers
3k views

What's a safe and portable way to split a string in shell programming?

When writing a shell script, I often want to split a string. Here's a very simple example: for dir in $(echo $PATH | tr : " "); do [[ -x "$dir"/"$1" ]] && echo $dir done This will ...
6
votes
3answers
1k views

Tar piped to split piped to scp

So I'm trying to transfer a bunch of files via SCP. Some of these are too large to be stored on the recipient (Android phone, 4GB file size limit). The sender is almost out of space, so I can't ...
3
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5answers
287 views

Regex match in CLI

Is there something like a logical for the cli? I want to achieve this mv -t newfolder *.(png|jpg) so that alls jpg and png files are moved into newfolder. I know it could be done with mv -t ...
3
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4answers
2k views

Unix - how to fetch files based on the part of a filename that is date

Say I have files say like AA_XX_20111208 AA_XX_20111207 AA_XX_20111206 AA_XX_20111205 AA_XX_20111204 AA_XX_20111203 So using the date part, how can i fetch previous 2 month files ? For e.g. this ...
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2answers
479 views

How to move files from one directory to a nested directory using SSH?

I'm new to SSH. I would like to know how to move all the files, not the folder or directory, to an existing folder or directory two levels down.
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1answer
36k views

How to create bootable flash for “efi-shell”

Current Intel server chipsets include a built-in "efi-shell" which appears to basically be a simplified 'NIX with a command set suitable for manipulating some nifty UEFI boot options. It is also the ...
3
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2answers
922 views

Can the shell warn me if a program is waiting for standard input?

Let's say I want to search for a string in a big file: grep foo bar.txt | less, but I actually type grep foobar.txt | less. Now, grep is waiting for me to type something on the terminal. It appears ...
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2answers
112 views

Reduce redundant logfile

I often have longer redundant log files, redundant in the sense that blocks of text repeat with minor changes. The length of the files makes it difficult to spot the actual information. I had the idea ...
2
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3answers
4k views

How to remove element from the list?

I have written a command that output a list of hostnames, e.g. : clab148node11 clab148node12 clab148node15 clab148node16 Now, I would like to remove those nodes that do not respond to ping. For ...
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1answer
5k views

What does sourcing a file mean in a shell? [duplicate]

Possible Duplicate: Different ways to execute a shell script What happens when I issue the following command: source devenv.csh How does it differ from running it just as devenv.csh ?
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4answers
37k views

Redirecting the content of a file to the command “echo”

I have a file named my_file.txt whose content is just the string Hello. How could I redirect its content to the command echo? I know I have the commands less, cat, more... but I need to do it with ...
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2answers
8k views

What is the difference between ping -w and ping -W?

What is the -w (deadline) flag in ping for? I cannot find a description of it in the ping man page; only for -W, which takes seconds as a parameter. What is the difference between them, and how can I ...
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4answers
29k views

How to send many commands to shell and wait for the command behind ends

Hello I have around 20 commands and I have to send all of this to Unix shell, and copy the result, but I don't know how to do it. I am not sure about what shell I have, because it is a small program ...
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2answers
18k views

Good method to compare time?

I need to check for the current time and abort the script if it is not proper time of day I am supposed to run it. Also, if anyone else runs it, it should abort. For example: I need my script to only ...
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2answers
2k views

Comparison of shells? [closed]

Do shells have any actual advantages or disadvantages? They can all run any binary, they all support pipes and > (output to file). Why would one choose bash over sh, or sh over ksh, etc? Why does ...
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1answer
126 views

How get program name that produced an IO error redirected to a LOG in a nohup command?

I have a program that executes other programs in the background. The main program would be programA, and the programs executed by the main one, would be program1a, program1b and program1c. I need the ...
2
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3answers
3k views

Linux Shell Script - Send command over TCP to Sharp Aquos

I'm writing a shell script that needs to send an 8 character string terminated with a x0d to a Sharp Aquos TV. An example is 'POWR1 \x0d' (POWR1 followed by three spaces and LF) The documentation ...
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1answer
2k views

Outputting last modification date to another file?

I'm trying to read the number of lines in a file, and the last modification date of that file (e.g. if it was last modified Jan 18, 2013, it should output 2013-01-18), then append the data to the ...
3
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1answer
260 views

Passing all files of specific filetype in current and subdirectories

I have constructed an elaborate 500+ character command with many arguments and switches to autosign multiple PDF documents. I'm using JSignPDF and I'd like to use it's batch mode including the ...
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3answers
4k views

How to execute a bash script on multiple directories?

I have a conv.sh script that loops over MP3 files in the current directory and converts them into OGG. I have also several directories {F1, F2,..., F20} at /path/to/Files/. How should I execute conv....
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3answers
2k views

Finding lists of files with specific permissions

I looked into the find command and came up with find . -maxdepth 1 -perm 521 > test.txt to output the permissions to a text file, but is it possible to do it just using, for example, simple ...
8
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2answers
362 views

Difference between [[ $variable ]] and [[ -n $variable ]]?

In bash, are [[ $variable ]] and [[ -n $variable ]] completely equivalent? It appears to be the case judging by the output below, but I see both forms of usage prevalent in shell scripts. $ z="abra" $...
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votes
4answers
1k views

What are commands to find shell keywords, built in functions and user defined functions?

I was discussing with my friend on how the commands are parsed in the shell, and he told me that bash searches the command in following order List of aliases List of shell keywords List of ...
3
votes
1answer
912 views

Why does sendmail work differently in different shells?

The following code works when I directly run it in bash shell: SUBJECT="SUBJECT-"`date`; MAIL_FROM="abc@site.com"; MAIL_TO="abc@site.com"; MAIL_CC="abc@site.com"; MAIL_FILE="/path/of/html/body.html"; ...
8
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5answers
3k views

mkdir -p for files

mkdir -p will create a directory; it will also make parent directories as needed. Does a similar command exist for files, that will create a file and parent directories as needed?
3
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5answers
636 views

Copy Sequential Files

I have 12 files named dmp_000, dmp_001, etc, all the way to dmp_011. I would like to copy all of them to rdmp_000, rdmp_001, and so on, sequentially so the numbered files coincide. There must be an ...
3
votes
4answers
5k views

How to pipe the stdout to a file if the current command is already being piped through gzip

So I have this command I need to run then disown: innobackupex-1.5.1 --user=root --password=**** --stream=tar ./ | gzip - > /data/myfile.tar.gz How do I pipe any output to a file? adding ...
7
votes
4answers
669 views

OpenSSH - map aliases in ~/.ssh/config to IP addresses in command line

Is it possible to query ~/.ssh/config in the command line? Let's say I would like to retrieve what IP address does the particular alias point to in a separate program, is it possible?
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6answers
21k views

How can I switch between different audio output hardware using the shell?

I use my laptop with an external monitor which has speakers. When the monitor is attached through HDMI I can switch (using the GUI: Sound Setting --> Hardware) between the normal laptop audio output ...
5
votes
2answers
4k views

bourne shell if [ -e $directory/file.$suffix ]

I've been looking inclusive I even checked the if manual for bash and tried in cli mode. #!/bin/sh CONFIG_DIR="/var/opt/SUNWldm/" read option if [ $option -eq 9 ]; then ret=1 elif [ -e ${...
1
vote
2answers
3k views

Parsing string by awk and get only elements without pipes or semi colons

I would like get this string line AUGUSTYN|Stanisław|3589238 without | and : I tried something like that: cat baza|grep "AUGUSTYN" -n|awk -F '|' '{print $1,$2,$3,$4}'` (baza is my file with ...
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1answer
440 views

how to setarch for each bash session

I am using bash as my default shell. I don't have root access. But I would like to customize my bash by setarch. So the question is how to do this automatically? Currently, I have to manually run "...
3
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1answer
335 views

No output from inotifywait | awk

I'm attempting to use part of a one-liner found here: Script to monitor folder for new files? When I try the following procedure I get no output whatsoever and I cannot figure out why. In terminal ...
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1answer
145 views

Unsure about the behaviour of my script when writing to log file

I have a very simple ksh script and at certain points I want to write to a log file. I use the following commands in two places... print "Directory listing 1:\n" > ${LogFile} ll >> ${LogFile}...
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1answer
4k views

What are special prompt symbols for busybox's sh support?

I want to setup a time prompt on PS1. But, there is no document about what are symbols the busybox support. Is there any one know? Here are all which I knew. PS1='\u@\h: \w \$'
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2answers
2k views

Setting a shell variable in a null coalescing fashion

I'm really fond of "null coalescing", where you can set a variable to the first "non-null" value in a list of things. Many languages support this, for example: C#: String myStr = string1 ?? string2 ?...
3
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2answers
820 views

$BASHPID And $$ differ in some cases

I'm reading "BASH pocket guide of Oreilly". It said: The process ID of the current Bash process. In some cases, this can differ from $$. Above explanation , explained $BASHPID variable. ...
4
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3answers
3k views

Find functions, commands, and builtins [duplicate]

Possible Duplicate: Executing user defined function in a find -exec call Suppose I have the following bash code: !#/bin/bash function print_echo (){ echo "This is print_echo Function" $1;...