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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-4
votes
1answer
31 views

Simple bash script to print prime numbers from 1 to 1000 [on hold]

How can I make a POSIX script that will print all the prime numbers from 1 to 1000? Lots of thanks
0
votes
1answer
40 views

meaning of [ $? -ne '0' ]. (shell script)

could anyone tell me what the following command means? I'm reading a shell script and studying what it does. But at the end of the script, the following commands appeared. I have no idea what it ...
56
votes
11answers
65k views

How do I convert an epoch timestamp to a human readable format on the cli?

How do I convert an epoch timestamp to a human readable format on the cli? I think there's a way to do it with date but the syntax eludes me (other ways welcome).
16
votes
9answers
29k views

Generate random numbers in specific range

After googling a bit I couldn't find a simple way to use a shell command to generate a random decimal integer number included in a specific range, that is between a minimum and a maximum. I read ...
1
vote
1answer
934 views

Shell Script Help - Automatically assign users to group

Recently, I have just started to learn linux and I am currently trying to make a shell script that can automate the task of creating user accounts, assigning them passwords and then assigning them to ...
0
votes
1answer
26 views

linux unbuffered compression options

I'm working on a embedded system and due to persistent memory restrictions, I need to compress a log file "on the fly". My objective is to have a one liner inside a script, which would look like ...
-4
votes
3answers
41 views

Write file names in to a file

In a directory I have X.txt,Y.txt,Z.txt files. I want to move these filenames into a single file like below: Out_file.txt X.txt Y.txt Z.txt Any unix command to achieve this?
1
vote
1answer
22 views

Comparing original & backup folder, then deleting non-existing files

I'm using Raspbian jessie (ubuntu). I made a .sh that makes a backup .img of everything (excluding mnt, tmp, run, dev, boot, etc.) and let this run once a week with crontab. It checks for modified ...
1
vote
0answers
23 views

Getting Busybox Cron to work on Qemu ARM VM [on hold]

I created a .sh script, then tried crontab -e and entered * * * * * /etc/cronscript.sh, then tried to start it by typing crond. It looks like its trying to do something once per minute, but not my ...
3
votes
1answer
48 views

How to create an alias for two Git commands that use a parameter? [duplicate]

I regularly have to delete a local and remote Git branch. Therefore, I run the following commands: $ git branch -d feature-branch $ git push --delete origin feature-branch Since I mostly execute ...
0
votes
1answer
30 views

Listing files with a certain extension

I'm suppose to write a command that would list all files that end in .tx with an optional t at the end. So far all I got is listing the files that end in .tx which is: ls *.tx Now my problem is ...
1
vote
2answers
616 views

How to rename multiple files using find

I want to rename multiple files (file1 ... filen to file1_renamed ... filen_renamed) using command find command: find . -type f -name 'file*' -exec mv filename='{}' $(basename $filename)_renamed ';' ...
88
votes
4answers
77k views

How to get the pid of the last executed command in shell script?

I want to have a shell script like this: my-app & echo $my-app-pid But I do not know how the get the pid of the just executed command. I know I can just use the jobs -p my-app command to grep ...
0
votes
0answers
12 views

My terminal is giving unformatted results (output) after upgrading to Ubuntu 15.10

Whenever I run g++ to compile any C++ code, My terminal is showing some weird output. Even when I do like man ls And this happened from the moment that I upgraded from Ubuntu 15.04 to Ubuntu ...
1
vote
1answer
26 views

How to get file descriptor number of a output and how to redirect all of them at once

Lets take this command for example $ time ssh ec2 ls www apps real 0m0.554s user 0m0.004s sys 0m0.000s $ time ssh ec2 ls 1>/dev/null real 0m0.554s user 0m0.004s sys 0m0.000s ...
13
votes
3answers
3k views

How can I redirect `time` output and command output to the same pipe?

Suppose I have a binary called foo. If I want to redirect the output of foo to some other process bar, I could write ./foo | bar. On the other hand, if I wanted to time foo, and redirect the output ...
13
votes
2answers
10k views

How do I time a specific command?

(The linux equivalent of TimeThis.exe) Something like: timethis wget foo.com Receiving foo.com ... wget foo.com took 3 seconds.
34
votes
2answers
15k views

How to run time on multiple commands AND write the time output to file?

I want to run time command to measure time of several commands. What I want to do is: Measure the time of running of all of them added together Write the time output to a file Write the STDERR from ...
1
vote
3answers
35 views

Run a command over directories with name recursively

I have the following directory structure in AIX. codeRepo/REPO1/AREA1/objects codeRepo/REPO1/AREA2/SUBAREA1/objects codeRepo/REPO1/AREA2/SUBAREA2/objects From codeRepo I want to run chown myUser * ...
1
vote
2answers
56 views

Crontab not running a shell script

Using account alex, I created: ~/pocketmine/pocketmine.sh When I manually run this using the same account, alex: cd pocketmine ./pocketmine.sh start It runs fine. I have added this to ...
3
votes
2answers
28 views

Run in background but not discarding the output

I use a Git hosting. So I often run git push. I want to run git push in background, in order that me not to wait when it finishes but do other tasks in my terminal. But I don't want to run git push ...
0
votes
0answers
20 views

meaning of !(something) in shell [duplicate]

While searching for a way to move all files in a dir to one of its sub-folders, i came across mv !(something) something which should do the job - but only in bash. However i could not find why. in ...
1
vote
1answer
45 views

Combining strings command and grep: how to limit results to null-terminated strings

I have a feeling that it is strings which is thwarting my efforts here. The binary files I want to use strings on unfortunately yield several matches per file, even though it is a 100% rule that ...
-1
votes
2answers
38 views

how to login a user using shell script [on hold]

In my computer i have two user(tiger,jenk) now i want to create a shell script for login user "jenk" from user "tiger" i m try this code [tiger@pagaltiger mytask]$ echo -e "IncorrectPassword\n" | ...
0
votes
1answer
35 views

Only send email if disk usages exceeds 80%

My script is: abc=$(df -h | sed s/%//g | awk '{ if($5 > 80) print "Alert "$0;}' | awk '{print $2,$6}') \ && echo -e "Dear All, \n\n$abc\n\nABC" \ | mailx -s "Disk partition" ...
2
votes
1answer
17 views

Get current memory usage of a tmux session

As the title says. I need a way to the used memory of a current tmux session. I am not sure if that is even possible. I am using tmux to start multiple minecraft servers I'd like to know each servers ...
0
votes
3answers
65 views

To calculate average by taking command line argument

The task is that if input numbers: 4 1 2 9 8 Output=(sum of all except first_number_in_series)/first_number in series Then output average should be 1+2+9+8/(first_number_in series)=20/4=5 I have ...
0
votes
2answers
35 views

How do I permanently remove an Alias from my Shell

When I was not near my computer some guy got it and set an Alias for ls in my root folder. He set it to 'yes NeverGonnaGiveYouUp'. So now when im in my root folder and type ls I get an infinite loop ...
3
votes
3answers
35 views

Can the Bash shell “Ignore” Excess copy-paste text?

Say, I have a "Quick&Dirty" Perl script in a gui text editor, and I start the Perl interpreter in a terminal window which is running Bash. I can copy-paste the Perl script to the terminal & ...
13
votes
5answers
10k views

How can I kill and wait for background processes to finish in a shell script when I Ctrl+C it?

I'm trying to set up a shell script so that it runs background processes, and when I Ctrlc the shell script, it kills the children, then exits. The best that I've managed to come up with is this. It ...
0
votes
2answers
35 views

Which location does shell assign normal variable?

As you know, bash shell itself is also process. If I use command export a=c, then shell dynamically allocates variable a into location where environment variables are reside.(This environment section ...
11
votes
3answers
970 views

Escape sequences in output of script called from ncurses application

I'm currently running mcabber as my Jabber client (which uses ncurses) in a tmux session on my homeserver. Locally i run iTerm2 as a terminal emulator, which supports the triggering of growl ...
0
votes
1answer
29 views

Kill command also kills other process

I have a very simple script, let's call it foo.sh. It's this: #!/bin/sh sxhkd & panel & where panel is a script (I won't post it here because it's very long and I don't think it would be ...
13
votes
5answers
315 views

How can I find the first missing directory in a long path?

Imagine I have a path that doesn't exist: $ ls /foo/bar/baz/hello/world ls: cannot access /foo/bar/baz/hello/world: No such file or directory But let's say /foo/bar does exist. Is there a quick way ...
0
votes
2answers
785 views

Use a script for a telnet session

I have a problem with my script. It seems my password is wrong. #!/usr/bin/expect set ip [lindex $argv 0] spawn telnet $ip set timeout 10 expect "Login:" send "administrator\r" expect "Password:" ...
4
votes
1answer
55 views

Are there non-interactive login shells?

I know what the difference between interactive/non-interactive and login/non-login shells are, but it seems like in practice there's never going to be a non-interactive login shell unless you have ...
1
vote
3answers
30 views

How do I organize and cut this portion of a directory into a file?

I'm new to unix and I'm not sure how to name my title but my main objective is to copy the contents of a directory and send it to a file. Then cut out the directory location to just have the name. ...
0
votes
1answer
37 views

Unexpected end of file in .bash_profile

When I do source ~/.bash_profile I get this "line 14 syntax error: unexpected end of file" error, I tried to delete the last line for no avail. Thanks # Get the aliases and functions if [ -f ...
12
votes
3answers
266 views

Why is 'ls' suddenly surrounding items with spaces in single quotes?

I just noticed that on one of my machines (running Debian Sid) whenever I type ls any file name with spaces has single quotes surrounding it. I immediately checked my aliases, only to find them ...
1
vote
2answers
19 views

bash adding a filename to an alias command [duplicate]

I have an alias to a ffmpeg command to start recording a session like this: alias sreq='ffmpeg -f x11grab -r 24 -s 1024x768 -i :0.0 -qp 0 -c:v libx264 -preset veryslow' I can just type sreq ...
-3
votes
0answers
16 views

Removing intermediate line breaks in muliple columns except the last new line character [closed]

Suppose If I have the data like this Col1|Col2|Col3 <br\> 123|abc\n<br\> xyz\n<br\> |abc\n<br\> def\n<br\> other rows<br\> <br\> In the above newline ...
0
votes
0answers
31 views

How to get curl progress bar in terminal?

I'm using curl to upload files from a bash shell. I know there's the option --progress-bar which is supposed to give an upload progress indicator, but no matter what, I can't get it to show. I do ...
0
votes
2answers
99 views

Why does the cd command handle STDIN different than other commands?

Commands like cd cannot have output piped to them in order to change directories--they require command-line arguments. Why does the cd command (and those similar to it, such as mv, cp, & rm) not ...
3
votes
4answers
14k views

Remove ^M character from log files

Remove ^M character from log files. In my script I redirect output of my program to a log file. The output of my log file contains some ^M (newline) characters. I need to remove them while running ...
1
vote
0answers
50 views

Some commands are no longer responding?

I have a Debian based distribution & lately a problem has been encountered when trying to execute the gcc or man command's (And probably other commands I haven't found yet). When I type them in ...
3
votes
4answers
413 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 ...
4
votes
2answers
1k views

Replace a substring of filenames in a directory

There exists a directory, which includes several levels of sub-directories. Under these directories, there are a set of files whose names include a common word, e.g, .cc. How can I replace the .cc ...
9
votes
3answers
1k views

Writing a character N times using the printf command

I found the following command to repeat a character in Linux: printf 'H%.0s' {1..5000} > H.txt I want, for example, H to repeat 5000 times. What does %.0s mean here?
0
votes
1answer
41 views

Kill a running shell script, and kill all process running within it

I have a shell script running in the background, which runs 5 different jobs. When I run the shell script all 5 jobs start running in order. When I kill this shell, whichever process is running, will ...
1
vote
1answer
26 views

Can Bash tell an interactive SSH session from an in-line SSH session?

I have a Bash script that needs to be run from an interactive prompt, due to environment variables and configuration that only seems to be read when actually logged into a session. Examples below: ...