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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48 views

How to classify these lines in this ASCII file

The ASCII file I have is this: a 1 2 3 1223 b 1 2 3 5 3344 1223 c 1 2 34 a 4 5 c 123 How do I collect the lines below a,b,c respectively? Q: What would I do to get the lines below? a 1 2 3 1223 4 ...
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1answer
23 views

zwrite handling of “@” symbol

I've been using zwrite to create simple message popups in AIX, and it handles @ symbols weirdly, even when they're strong quoted. I'm running these commands in ksh. As an example, echo '1 @ 2 @@ 3 ...
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1answer
41 views

Create tar files from shell script with current time stamp

I am trying to create a shell script which will back up my git codebase and save in a specific back up directory with current days name So far I have : #!/bin/bash branch="master" if [ $# -eq 1 ] ...
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6answers
251 views

Replace \n with blank in a file

I want to replace \n with blank Input file1 A\n D\n Output file2 I want A D I tried below commands but not able to replace please do needful. cat OUT | tr '\n' ' '
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1answer
70 views

Run shell script from crontab after server stop/start/restart

I want to schedule a shell script in crontab that runs whenever server restarts. It should also run when someone starts the server after it stops abruptly or crashes. How to do so in crontab? Any ...
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1answer
25 views

How to have getopts functionality when just calling another function within the file

I'd like to have named parameters for my functions. I seem to only be able to use GETOPTS for the main function called from the command line. If I have multiple functions within one file is there ...
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2answers
22 views

Transform values in a line by first field

I was wondering if there is an easy way to do the following without writing a script. Transform 1234,"a;b;d" 2345,"e;f;g;h" to 1234,a 1234,b 1234,d 2345,e 2345,f 2345,g 2345,h
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2answers
47 views

Single or Double quotes when defining an alias?

I know that contents of double quotes are expanded, whereas the contents of single quotes are not, such that echo '$1' gives $1 where as echo "$1" gives <the argument - blank in this ...
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5answers
160 views

How can I use a wildcard to match just files, not directories?

I have a folder called home/homeLife I have a file called home1 home2 and home3 stored in /home I want to move all files that start with home* to home/homeLife/.. I typed mv home* /home/homeLife ...
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1answer
72 views

How to run privileged bash script as non-root? [duplicate]

I created a simple bash script which contains the command ifconfig. In general I want to execute such a privileged script to run as non-root user. I have tried hown root:users ./path/to/script.sh ...
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0answers
69 views

'cp:cannot access file' error in script?

This is the code: #!/bin/bash $REPORT_PATH='/data/operational/logs' cp "$(`ls -t | head -1`)" "$REPORT_PATH/new_file" This gives error 'cp:cannot access pda_param'. pda_param file is o/p of ls ...
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0answers
36 views

Higher-level wrapper for entr or inotifywait

I'm looking for a way to rerun a specific command as soon as any of the files in a subdirectory (perhaps minus selected excludes) changes. Use case I'm working on a project that is self-contained in ...
4
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2answers
42 views

stdin 'hop' over process?

Is there a way that stdin can 'hop' over a process? For example, in the following command, cat file | ssh host 'mkdir -p /some/directory && cat > /some/directory/file' This will send the ...
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1answer
77 views

Shell script printing blank $USER variable when executed by Smartd

I have created a script that smartd daemon (smartmontools) executes as per command below. DEVICESCAN -a -m email -M test -M exec /usr/share/smartmontools/my-script -n stand... Smartd appears to be ...
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1answer
219 views

Replacing white-space / characters with backslashes [duplicate]

I want to convert a bunch of mkvs to mp4s with the following command: for i in $(ls *mkv); do ffmpeg -i $i -vcodec copy -acodec copy $i.mp4; done; However, the filenames have whitespaces and ...
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2answers
47 views

Any special permission ssh remote command working on fifo file(aka named pipe)?

I need to redirect some strings to a fifo file with ssh remote command, but always got permission denied, the command I executed is: ssh rundeck@nagios1 sudo su - root -c 'printf ...
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1answer
17 views

I'm trying to deploy with git to a semi-managed vps, need to write a script to change owners

I'm trying to deploy my sites on my company's semi-managed vps server using this tutorial: https://www.digitalocean.com/community/tutorials/how-to-set-up-automatic-deployment-with-git-with-a-vps It ...
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1answer
38 views

Absolute path from user input without losing symlinks inside

Is it possible to convert in a shell script a user input path (absolute or relative) to the absolute path but without losing the symlinks inside, e.g. /a/b/c is the current user dir and c is a symlink ...
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3answers
47 views

How can I capture the common characters between two strings

I'm looking to compare two strings and capture the common part e.g. FILE0000010985.LOG FILE0000010999.LOG FILE0000011000.LOG If I compare 1 to 2, I want the output to be ...
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1answer
26 views

Generate SCP string

Generally when I am copying files from a local instance to a server, I find it difficult to generate the SCP string for the server to copy the files. I need to execute the following three commands ...
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1answer
24 views

find files with two types of extensions last modified over 30 days ago

I want to find all the files in a directory that have not been modified for at least 30 days and end in .xml or .out. This is my attempt to cobble together a couple of references to build the right ...
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3answers
44 views

Change Multiple (Including No) File Extensions

If I have a directory of files, where some files have an extension like .html and some files have no extension, how do I change them all to, e.g. .txt?
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1answer
24 views

Which way is safer to read data from /sys

I am attempting to write a program that will monitor the temperature of various hardware components. The language I chose for it is Java. Now there are two ways I could read the temperatures: a) Do ...
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5answers
184 views

How to get current working directory? [duplicate]

I want to have a script that takes the current working directory to a variable. The section that needs the directory is like this dir = pwd. It just prints pwd how do I get the current working ...
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4answers
55 views

Completely buffer command output before piping to another command?

Is there a way to only execute a command after another is done without a temp file? I have one longer running command and another command that formats the output and sends it to a HTTP server using ...
2
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2answers
34 views

Why is a variable passed to the su command, but not an array from the same scope?

In the example below, why does $var get passed to the su in the start function, but not the array modules ? #!/bin/bash var=cat modules=( one two three four ) start() { su gleventh -c "for i in ...
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2answers
57 views

Why would the prompt get overwritten?

p_ash-3.2$ cp some_file1234.html /some/loc/ation/ofthe/some_file1234.html.html_Backu Have been seeing this intermittent issue with the command-line, while typing longer lines as part of any command, ...
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1answer
91 views

remove lines where a field's value is less than or equal to 3 - sed or awk?

I need to remove every line that has a value of 2 or less in the 8th field (column). My data looks like this: 12-31 Airport 189 379 41 49.70946503 -124.91377258 2 2880 30.8 01-01 ...
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0answers
24 views

convert from one memory format to another and find the difference between them

Using shell scripting, how can I convert from one memory format to another and find the difference between them? I want to compare current rate and previous memory rate (Where we need to compare ...
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votes
2answers
28 views

How to search parenthesis by ack

I want to search for a parentheis ( using ack, but neither using ( nor \( worked. The first one ("(") is recognized as a multiple line command. The second one ("\(") is treated as an invalid regular ...
1
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1answer
56 views

how to locate a name-not-specified file in bash? [closed]

I have a bash like this to easily upload a file to my server: FILE=../"$1"/1.txt scp 1.txt remoteserver #upload the file to a remote server. The $1 is for input directory and I have a lot of ...
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2answers
912 views

Renaming the current directory from a shell - possible?

Is it possible to rename the current working directory from within a shell (Bash in my particular case)? If I attempt to do this the straightforward way, I end up with an error: ...
1
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1answer
32 views

Specify the type of field to modify in a file

I have a list of clients, "code", "name", "location", "etc" and I want to make a function that asks the employee to give the client's code and then the field he/she wants to change. For example, ...
2
votes
3answers
78 views

Calculate date difference between Last modified date of a file and NOW using shell script

I am trying to calculate the time elapsed since the log file was last updated. I guess following commands will be used lastUpdate=$(date -r myLogFile.log) now=$(date) How can I subtract them and ...
3
votes
5answers
178 views

Pick the latest file based upon the sequence number given in the file name

I have a requirement, I have few files in a directory, I need to pick the oldest one for processing. For Exp: I have below files in /tmp directory: Sample_0000237826-001_xyz.dat ...
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0answers
14 views

sending NEDIT to background on launching

I have this problem - for opening nedit it will open in the foreground. Then either you open it using & ex- prompt> nedit & is there any way where I can open nedit directly in the ...
2
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4answers
63 views

space check on unix machines

I am having space issues on 1 of the UNIX servers. I am executing the below command to check the space utilization. But this command is very slow and takes hours of time to give the result. du -sg * ...
0
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1answer
44 views

Error with sed on MAC OS X invalid command u

Im french sorry in advance for my bad english... So i have an error on MAC OS X when im using sed sed -i '' '/user_pref("mail.identity.id1.reply_on_top", 1);/ a\ ...
1
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1answer
106 views

loop through multiple folders and perform commands then write to file

I have 10 folders that I want to loop through while executing the following command: awk 'FNR > 1' *.csv | sort -sk 1,2 | sort -sk 3,3 > ${f}_appended.dat With a for loop wrapper, like ...
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1answer
65 views

Shell script runs diffrently based on working directory.

I have a script which runs differently based on current working directory. Basically it processes an .ini file and takes parameters from it and runs mysql backup. Script is running as root user. ...
0
votes
1answer
31 views

Having problem with mysql dbdump when password starts with special character

I am trying to take a db backup with a php file that is running from a cronjob. It was running fine when I tested with sample db. But when I used the actual db there was an error. I am using ...
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votes
1answer
48 views

Can you please tell me what is wrong in below script?

script : it is giving below error. please help me. basically i need to get email when memory exceeds some limit. error : ./vamsitest.sh: line 10: [: missing `]'   #! /bin/bash # Total memory ...
0
votes
1answer
20 views

Unable to extract to specific directory

I am trying to extract to file to specific directory but it doesn't produce result Operating system : SunOS Command: zcat /export/home/tceng/Desktop/temp/3.tar.Z | tar -xf - -C ...
2
votes
1answer
39 views

Windowless xterm? (Faking a terminal for a process)

I'm fighting with a rather odd problem with Matlab. The startup script is located in /opt/matlab_2013b/bin and is called matlab. When I run it in terminal, it works fine. But I want to make a ...
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3answers
68 views

How to use password in shell scripting

I am writing a script which greps for for multiple files from 3 log files. One of the log file is created as superuser and every time it executes it prompts for password. How do I put it the same ...
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0answers
37 views

delete non important characters from command output

the version command in my Linux machines display the following output version Red.Hat.OS. release..........5.5 APP.Release.............4.2.0.0-02 how to remove the middle "." dot character ...
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2answers
74 views

What is difference between Power broker utility and sudo command?

I got a little clarity with the following answer on this Source Symark Power Broker is a commercial package. Sudo is an open source tool.
4
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2answers
278 views

How to echo `single quote` when using single quote to wrap special characters in shell?

I'm reading shell tutorial today from http://www.tutorialspoint.com/unix/unix-quoting-mechanisms.htm In which it mentions: If a single quote appears within a string to be output, you should not ...
1
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1answer
39 views

When did bash quit exporting SHELL?

I upgraded a Debian box from stable to Jessie and I noticed that SHELL is no longer exported, so screen and similar programs start dash for subshells instead of bash. When was this change made and ...
10
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4answers
715 views

Spaces next to pipes

I've seen history | grep blah and history |grep blah; and history|grep blah also works, though no one ever seems to use it. Is there any significance in the spaces (e.g. piping to/from different ...