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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locate alias with find

On small systems where there is no locate installed, How would an alias look like that gets the same result as locate? I can imagine find can produce the same output so an alias could look like ...
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3answers
2k 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" ...
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2answers
3k views

variables in find command and more shell problem [duplicate]

Possible Duplicate: Recursive rename files and directories I wrote the following script: #!/bin/bash SAVEIFS=$IFS alias export='export' IFS=$(echo -en "\n\b") find $1 -name "*" ...
2
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2answers
55 views

What's the appropriate way to do “mv ./* ./subdirdir/”? [duplicate]

Under the current directory I have a number of files, and one directory. I would like to move all files to the sub directory: mv ./* subdir/ cannot move ./subdir to a subdirectory of itself... The ...
28
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7answers
41k views

Execute a command once per line of piped input?

I want to run a java command once for every match of ls | grep pattern -. In this case, I think I could do find pattern -exec java MyProg '{}' \; but I'm curious about the general case - is there an ...
2
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3answers
66 views

How to kill this process in bash

I am trying to interface my homemade Raspberry Pi-powered arcade machine with a coin acceptor, and for that I: use a shell script (named gameplay) which starts the game emulator (MAME) when a coin ...
0
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2answers
514 views

Making A Shell Script To Write To XML File

I am writing a shell script to make writing my RSS a whole lot easier. Right now I am stuck at how to properly edit my files. See, I want the program to take in data from me, and then save those to ...
2
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3answers
38 views

Find a directory which contains all the files in my list

I have moved a file, which makes a reference to four other files with the same parent directory. And now I am stock trying to figure out which parent directory that is since there a number of files ...
5
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1answer
94 views

Bash Script — ffmpeg not being invoked as expected

I'm working on a bash script to convert my music library to ogg* but executing the right command is somehow eluding me. This is the line that should accomplish it: ffmpeg -i "${file}" -f flac pipe:1 ...
4
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3answers
259 views

Exiting a shell script with nested loops

I have a shell script with nested loops and just found out that "exit" doesn't really exit the script, but only the current loop. Is there another way to completely exit the script on a certain error ...
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2answers
36 views

shell script not running using crontab

This is my script mboxutil -l > n.txt sed 's/^.*user//' n.txt > n1.txt cat n1.txt | sed 's/^.//' > n2.txt sed 's/\/.*//' n2.txt > dss_list.txt rm -f n.txt rm -f n1.txt rm -f n2.txt sed ...
16
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1answer
340 views

What does it mean to have a minus sign as the first character of a command in htop output?

In htop, or other commands that show process status, all bash processes have in the command column /bin/bash but one process has in the command column -bash What does it mean?
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1answer
32 views

Execute bash snippets directly in shell? [on hold]

Is there any way to execute small bash snippets in the shell? If you don't want to edit a file again and again and test it by executing it again and again (in fact by jumping forth and back between ...
0
votes
2answers
29 views

How to find file that has read permissions from root directory?

I am trying to find files with read permissions from root directory and save them under /home/student/abc direcory: find / -type f -perm a+r -exec cp /home/student/abc {} + but it shows me the ...
2
votes
1answer
28 views

Start sh in a specified directory from inittab

I am currently working on an embedded Linux system. For it to be similar to our other products I need to have it start a shell in a specified directory on boot, accessible using the serial port. For ...
70
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16answers
68k views

How can I get distribution name and version number in a simple shell script?

I'm working on a simple bash script that should be able to run on Ubuntu and CentOS distributions (support for Debian and Fedora/RHEL would be a plus) and I need to know the name and version of the ...
3
votes
0answers
73 views

Peculiar Solaris integer comparison behaviour

This one caught me unawares! We have a Solaris machine (version: SunOS 5.8) hosting a pivotal script/process which has been running for many years without complaint. We recently had cause to have a ...
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0answers
17 views
2
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1answer
16 views

Running make for LFS complains about [ and about missing gawk

I'm having a strange error when I'm trying to start the make process for LFS using the LiveCD SVN Trunk. When I go to run make it gives me; $ make /bin/sh: 1: [: -ne: unexpected operator -e Missing ...
6
votes
4answers
802 views

Add a newline into a filename with `mv`

It's a serious question. I test some awk scripts and I need files with a newline in their names. Is it possible to add a newline into a filename with mv? I now, I can do this with touch: touch ...
2
votes
1answer
63 views

Convert IP Address to Coordinates using database

I have a file which contains IP and I wanted to compare it to Coordinates using a local database (instead of API). I tried following a process and break down to pieces and created scripts referring ...
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votes
0answers
19 views

terminate when user type -1 [on hold]

#!/usr/bin/env bash # Above, get the path to BASH from the envvironment. # Below, you could just set the total mileage here. total_mileage=0 # Below, start from zero and count up for the three ...
1
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1answer
54 views

Extracting trace information using gawk

I am new to awk programming and am using gawk to extract trace information from a mrt file in order to use it further for analysis. I have successfully been able to extract trace information from a ...
6
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3answers
265 views

Should I use a slash at the end of path variables in shell script or not? [on hold]

Today when writing my shell script. A question suddenly comes to my mind. Since cd /target_dir and cd /target_dir/ both works. Should I add a slash at the end of my path variables in a shell script? ...
3
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1answer
615 views

KSH styling text based menu using STDERR

Is it possible to format the STDERR in order to have a better looking menu using the select command? I have a simple select select oChoice in $(<tempMenu.menu) ; do case "$oChoice" in ...
12
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1answer
130 views

Update bash history on others terminals on exit of one

I know this question has a similar interpretation, as its asked here keep updating (and duplicated here). But what I'm trying to achieve is a bit different. I don't like the idea of my prompt ...
4
votes
3answers
158 views

awk and newlines in the input data

I want to find files in a directory and identify by their mimetype, not by the extension of the files. I'am using this command to determine the mime type: % find . -type f -print0 | xargs -0 -I{} ...
1
vote
1answer
43 views

Batch move all files from subdirectories to parent directory, but files have same name

I have many files in sub-directories that I would like to have all moved to the parent directory. Ex: 20150530XXXX/1.jpg 20150530XXXX/2.jpg 20150530XXXX/3.jpg 20150530XXXX/4.jpg 20150531XXXX/1.jpg ...
53
votes
2answers
1k views

Security implications of forgetting to quote a variable in bash/POSIX shells

If you've been following unix.stackexchange.com for a while, you should hopefully know by now that leaving a variable unquoted in list context (as in echo $var) in Bourne/POSIX shells (zsh being the ...
0
votes
1answer
58 views

route -n gives output “route: fscanf”

If I boot my system and no interface has an IP address I get the above output. However if I give an interface an IP, even if I remove it again, this will disappear. Why does this happen? Is it that ...
2
votes
2answers
134 views

bash completion in Posix mode

I would like to use an interactive Posix bash shell but the autocomplete feature doesn't work. When I type the Tab character it simply prints a tab. The tab completion works only when I'm in a ...
16
votes
4answers
13k views

Solving “mv: Argument list too long”?

I have a folder with more than a million files that needs sorting, but I cant really do anything because mv outputs this message all the time -bash: /bin/mv: Argument list too long I'm using this ...
1
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1answer
39 views

CasperJS and PHP In Cron Job Cannot Open Files, Works Fine When Run Manualy

I recently got a new DigitalOcean LEMP environment with Ubuntu. I tried making an SH script that uses CasperJS to scrape data from an external website to a JSON file, and a PHP script to parse the ...
69
votes
10answers
72k views

How to add a newline to the end of a file?

Using version control systems I get annoyed at the noise when the diff says No newline at end of file. So I was wondering: How to add a newline at the end of a file to get rid off those messages?
0
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2answers
51 views

How do you search ! in man sed?

You cannot search ! directly because it puts process behind. For instance, you cannot search ! in sed man. How can you search ! in man?
0
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1answer
46 views

Issue a command in each directory

I have 3 directories: dir1 contains two subdirs. In every subdir there is a slackbuild. I want to build all slackbuilds, staying in the parent directory. I have tried (cd *;sh *ld) But it only ...
88
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7answers
8k views

Why is cd not a program?

I've always wondered why cd isn't a program, but never managed to find the answer. Anyone know why this is the case?
4
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1answer
7k views

Linux - Sending a command to a screen through a shell script? [duplicate]

I'm trying to figure out how to make a script that will be able to send commands to a screen that will execute within whatever the screen is doing. Is this possible, and if so, how is it done? I've ...
2
votes
1answer
117 views

Autocomplete issue in bash with equal sign (=)

I am trying to make autocomplete work and wroted a piece of code to demonstrate an issue I faced up: $ cat completion.sh function _completion_command() { compopt +o bashdefault +o default +o ...
2
votes
2answers
52 views

ssh command with quotes

I have an odd error that I have been unable to find anything on this. I wanted to change the user comment with the following command. $ sudo usermod -c "New Comment" user This will work while ...
0
votes
1answer
43 views

Practical usage of “shift” shell builtin command?

I checked the /usr/bin/ssh-copy-id(part of openssh-client package at least under Debian) shell-script and it contains following if-statement: if [ "-i" = "$1" ]; then shift # check if we have 2 ...
5
votes
6answers
482 views

How do I check if a variable exists in bash?

I need to check a variable's existence in an if statement. Something to the effect of: if [ -v $somevar ] then echo "Variable somevar exists!" else echo "Variable somevar does not exist!" ...
1
vote
1answer
42 views

Move files from multiple directories to another system

Let's suppose I have a folders in the source system: AB1, AB2, AB3. And I have the same folder names AB1, AB2, AB3 in the destination system. I want to move AB1 files to AB1 and AB2 files AB2 and ...
4
votes
2answers
40 views

How can I disable bash traces?

For any command that I execute in the terminal a comment like + command appears. For example for ls it shows + ls --color=auto.
4
votes
4answers
926 views

How can I make shell aliases available when shelling out from Vim?

In my .zshrc, I declare some aliases. Eg, which dbstart shows the contents of that alias. If I open vim from that shell, it is a child process. In Vim, I can run shell commands with :! some_command. ...
1
vote
2answers
53 views

How do i search for certain sections of a file and then extract only relevant information within that section?

So I have a text file that is a server report and has about 1000 lines of information in it. I'm trying to write a script that can search the report for only certain pieces of information I'm looking ...
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7answers
6k views

How to insert the content of a file into another file before a pattern (marker)?

File1 contents: line1-file1 "1" line2-file1 "2" line3-file1 "3" line4-file1 "4" File2 contents: line1-file2 "25" line2-file2 "24" Pointer-file2 "23" ...
13
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3answers
2k views

What are the shell's control and redirection operators?

I often see tutorials online that connect various commands with different symbols. For example: command1 | command2 command1 & command2 command1 || command2 command1 && command2 ...
18
votes
3answers
575 views

Use of ^ as a shell metacharacter

I wrote a small script today which contained grep -q ^local0 /etc/syslog.conf During review, a coworker suggested that ^local0 be quoted because ^ means "pipe" in the Bourne shell. Surprised by ...
47
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6answers
20k views

How to check if a shell is login/interactive/batch

I think I understand the differences between an interactive, a login and a batch shell. See the following links for more help: What is the difference between a 'Login' and an 'Interactive' bash ...