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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6answers
81 views

Is there a way to find out the number of lines from a command output?

I am trying to compare command outputs between two servers. I want to find out the number of lines from the output of commands such as ls -l. Is there a way to do so? So far I have not found anything. ...
2
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1answer
48 views

History in the Almquist shell in the NetBSD

In NetBSD /bin/sh is a modified version of the Almquist shell. With the command fc -l it is possible to view the last 16 commands typed in the prompt in the current session and not the older ones. ...
2
votes
1answer
33 views

stdout is empty

When a run the command: cellprofiler --get-batch-commands "/users/pmrotem/CellProfiler/example_project/output/Batch_data5_8.h5" in the shell, I get an output: CellProfiler -c -r -b -p ...
4
votes
3answers
113 views

zsh's “echo SomeText >> **/filename” in other shells

I need to fill all files with a specific filename (recursively) with a text. In zsh this can be done with echo SomeText > **/TheFileName I search generic solutions for sh-compatible and/or tcsh ...
3
votes
4answers
78 views

Protected environment variables?

Are there names of environment variables that cannot be overwritten by the user/a call to setenv? As I understand from POSIX1.2008, any process may edit the environment block, but must avoid ...
1
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1answer
54 views

Getting the parent path from a script

I have a bash script foocaller, which calls a ruby script foo: foocaller /path/to/foo Within foo, I want to get the path of foocaller. Following this suggestion, I put the following code to do ...
28
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3answers
2k views

What does `{ { (exit 1); exit 1; }; }` mean?

I quoted the next code snippet from config.status generated by configure. if test ! -f "$as_myself"; then { { echo "$as_me:$LINENO: error: cannot find myself; rerun with an absolute path" >&5 ...
-1
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1answer
28 views

Make an alias that does an alias command

I have to make an alias that will do the alias command. It has to "replace" the alias command and the user has to feel no difference..
4
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2answers
98 views

Execution order with multiple commands

I'm relatively new to Linux and I'm working on a CronTab for scheduled backups. I figured out how to do multiple sequential jobs with ; and &&, but I'm unsure how the dependency affects the ...
2
votes
1answer
43 views

How to move a window to a different workspace using its ID, in bash?

Currently I have successfully used wmctrl -r :SELECT: -t 2 but something like wmctrl -r -i 0x03e00003 -t 2 does not work. How should I write the command in order to select the window to be moved ...
5
votes
1answer
72 views

What are the difference between those four commands (fifo, process substitution, redirection…)

My goal is to create a simple echo server using nc and a single fifo. I'm not looking for the best way to do it, I'm merely trying to understand the semantics of the following commands (when does fork ...
1
vote
1answer
52 views

Matching two files, line by line? [closed]

I have two files consisting of numbers. Now, I want to match the line of first file to all the line of second file and increasing the counter if the match is found. How to write the bash script for ...
5
votes
5answers
211 views

Serialize shell variable in bash or zsh

Is there any way to serialize a shell variable? Suppose I have a variable $VAR, and I want to be able to save it to a file or whatever, and then read it back later to get the same value back? Is ...
2
votes
1answer
56 views

Mysql synonym drop and create

I am running into the issue that, when the script is run, the MySql section of it isn't working or is droping the synonym. Is there something else i need to put into the command to have it log into ...
2
votes
4answers
69 views

Get the latest directory (not the latest file)

My folder parent has the following content: A.Folder B.Folder C.File It has both folders and files inside. B.Folder is newer. Now I just want to get B.Folder, how could I achieve this? I tried ...
3
votes
3answers
81 views

Can't open shell after changing default shell

I changed my default shell to zsh from bash in Ubuntu. I used the steps explained in http://github.com/sorin-ionescu/prezto and ran chsh -s zsh. After this, I couldn't able to log in to any shell as ...
2
votes
1answer
73 views

Why is my tar in a script behaving different than using tar manually

I'm writing a backup script for my email and cloud service. For simplicity, I only posted the mail-backup part here. Basically, I have a Host-Machine with some Virtual Boxes running in it. These ...
2
votes
5answers
508 views

How to use the sed command to only show the first column and last column in a text file

I need some help to figure out how to use the sed command to only show the first column and last column in a text file. Here is what I have so far for column 1: cat logfile | sed 's/\|/ /'|awk ...
1
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3answers
146 views

How to get a string between two special characters using Shell?

I want to get a string between two special characters. For example, /home/oracle/ggs/text.ext I want oracle/ggs in the above string. How can I do this using bash?
0
votes
0answers
27 views

Use FindBugs in Eclipse from terminal on Ubuntu

Is there any way I could use Findbugs from terminal to get all the bugs in my Java code and print it out to a text file? I want to write a script that goes through 100 java files ( this is already ...
4
votes
5answers
113 views

bash script [ x$1 = x ]

I am reading bash script I do not understand what is going there. #!/bin/sh [ x$1 = x ] What is going on the second line and what [ x$1 = x ] mean?
0
votes
2answers
91 views

How can I grep for broken HTML tags?

I want to grep through all my HTML files and see if I have any bad tags there, example <br> , <hr> and so on, that is the I want to see what tags are not closed in the HTML file. for ...
1
vote
1answer
61 views

upstart writing to syslog in a simple way

I have an upstart script that uses pre-start script exec >/dev/kmsg 2>&1 echo starting program # run my program here npm install node app.js end script to redirect output of a ...
6
votes
3answers
164 views

Shell script to search files for identical text entries

Here's a nice teaser for a shell scripting guru: Take a directory with several text files. Can be a few up to ~1000. All files contain an identifier on a given line (always the same line). Identify ...
0
votes
1answer
59 views

Pipe output from one command to another command's non standard input [duplicate]

I would like to do something similar to the following: which someapplciation | cd outputfrompreviouscommand The command which provides a directory and I would like to be able to make that output my ...
5
votes
1answer
80 views

What's the difference between “realpath” and “readlink -f”

I've read a lot about realpath command and how it has been deprecated with the readlink -f being now recommended. I have also seen in some places that the reason why realpath was introduced was for ...
3
votes
3answers
59 views

Print a string including single quotes and other special characters

How can I write this with an AIX script correctly? My requirement is to write this command in test.txt: clock=$(prtconf -s | awk '{print $4,$5}') I tried this command: print 'clock=$(prtconf -s | ...
3
votes
3answers
101 views

History of Bash globbing

Is there a historical reason why Bash "globbing" and regular expressions are not identical? For example, I believe that in Bash [1-2]* matches anything that starts with a 1 or a 2 followed by anything ...
0
votes
1answer
103 views

SQLPLUS withing shell script loops

Hello I am trying to run a loop and get the details of a project. I have these projects in my work space. How do I loop over the SQL code? #!/bin/bash workspace=$(sudo locate -r '/workspace$') ...
0
votes
1answer
38 views

Scripting error after bc command

I am trying to execute script contains the following: #!/bin/bash USED=`free -m | more | grep -v total | head -1 | cut -d':' -f2 | cut -d' ' -f18` CACHE=`free -m | more | grep -v Swap | tail -1 | cut ...
1
vote
2answers
76 views

Compare set of values from two files and print the output in third file in awk

Hi friends i have problem with comparing two files.I'll try my best to explain.I have two file f1 and f2 which i have to compare on basis of two sets Parameter(p) and Value(v). Basically f1 contains ...
3
votes
3answers
97 views

How do I pass a comand-line program a list of files from a directory?

I am trying to upload documents to my Microsoft OneDrive account using python-onedrive. The command I am using is this: onedrive-cli put Long\ Filename\ 1.jpg onedrive-cli put Long\ Filename\ 2.jpg ...
1
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1answer
63 views

Understanding behavior of subshell and stdout with pipe

Let us say I have .c file and corresponding executable (let us say foo) that takes in some input from stdin and then makes a sys call to /bin/sh. Feeding input to this executable like following: ...
2
votes
1answer
46 views

How can I receive input through notifications in bash?

When I get a chat message in Empathy, I get a notification in GNOME Shell. This notification allows me to input a reply directly, instead of having to switch to Empathy. Is there any way I can get a ...
2
votes
1answer
38 views

How do you implement totals from usage output generated by a program in a script so that they carry on sanely through repeated execution?

I have a script with a pipeline where the data is throttled by a program. Every 20 minutes, a throughput status is sent on stderr, and I simply redirect this to a file: command | cstream -t -512k -T ...
2
votes
1answer
276 views

ctrl c vs. ctrl z with foreground job

Ctrl+Z stops the job whereas Ctrl+C kills the job. Why is that? Wouldn't the other way make more sense? z@z-lap:~$ sleep 100& [1] 4458 z@z-lap:~$ sleep 200& [2] 4459 z@z-lap:~$ jobs [1]- ...
0
votes
3answers
56 views

Why doesn't source work when I call bash -c

I want to run a command that sources a script to take on some env. variables before executing, without sourcing them in my current shell. test.env export test=1 None of these commands echo the ...
1
vote
1answer
37 views

How to use one variable's name to refer to another variable? [duplicate]

a=2 pt2=3 echo $a 2 echo $pt2 3 How can I use echo $pt($a) to print the contents of pt2? An alternative is b=pt$a echo $b pt2 echo $[$b] 3
0
votes
0answers
41 views

Specific Jar file doesn't run on startup

I want to run a jar at startup, so I asked a question here. I was given a few suggestions, so I started from trying to create a script file and desktop file. I created a script file and desktop file ...
7
votes
4answers
700 views

I am using `&`: why isn't the process running in the background?

I know that I can append & to a command to run the process in the background. I'm SSH'ing into an Ubuntu 12.04 box and running a python program with $python program.py & -- but when I go to ...
1
vote
3answers
38 views

Shell command to remove the first string that is enclosed with slashes

I need a shell command(sed or awk is preferred) to remove the string that is enclosed within the slashes. For example If my string is /some/dir/example/ then the output should be dir/example/
1
vote
3answers
46 views

How to remove all FIFO files with a shell command

I can't find a shell command to remove all the FIFO files inside a directory. In fact, for the removal of directories, the rm command offers the options -d, --dir, but for FIFOs it offers no option. ...
3
votes
3answers
112 views

Environment variables are not set when my function is called in a pipeline

I have the following recursive function to set environment variables: function par_set { PAR=$1 VAL=$2 if [ "" != "$1" ] then export ${PAR}=${VAL} echo ${PAR}=${VAL} shift ...
4
votes
4answers
157 views

What is the Linux command to display how many file names in the directory end in two digits

What is the Linux command to display how many file names in the directory end in two digits? Using ls with a command like this : ls -l | wc –l *[0-9][0-9]
0
votes
1answer
53 views

Is there a way of copying only directories and not files in bash? [closed]

I want to copy only directories from a folder on a remote server to my server. Is that possible? Here is the code I have so far but it copies files and folders: scp -rq ...
2
votes
2answers
131 views

How to get previous year and previous month in solaris 8

How to get previous year and previous month in solaris 8? I have tried below command but none of them is correct: date +'%m' -d 'last month' date +'%Y' -d 'last year'
0
votes
1answer
34 views

Store restored files and directories in a separate directory

I have backup files in the form backup-date.tar and these files will be in a directory called backup. I am performing a restore by using tar -xvf backup-date.tar but the restored file is placed in the ...
3
votes
3answers
175 views

Return to directory location prior to cd-ing to home directory

As is well known, cd without an argument changes one's current directory to their home directory. I am wondering if there is any way, after using the cd command like this, to return to the directory ...
0
votes
1answer
93 views

How do you keep the password hidden when invoked during the su command?

This is the first time it has happened to me where I am using the su command and it actually displays the password on the terminal and doesn't stay hidden. Here is my code snippet: sshpass -p ...
7
votes
1answer
123 views

stderr over ssh -t

This sends output to STDERR, but does not propagate Ctrl+C (i.e. Ctrl+C will kill ssh but not the remote sleep): $ ssh localhost 'sleep 100;echo foo ">&2"' This propagates Ctrl+C (i.e. ...