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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2
votes
3answers
62 views

Remove files from listing that are created/modified on Saturday

I am not sure if it is possible. I do ls -l, it gives all the files in the current directory. Is there a way to say list only files that weren't created/modified on Saturday's with shell command?
2
votes
1answer
35 views

Problems with find, xargs and egrep

I this is what I what I'm trying to end up with (except working) find ./ -mindepth 1 -type f -mtime +60 -print0 | xargs -0 egrep -vZ 'vvv|iii' What am I doing wrong? $ ll total 0 -rw-rw-r-- 1 ...
0
votes
1answer
64 views

Command not found when run with sudo bash

I ssh into my machine and then, in order to run some commands, I need to sudo bash first. In an interactive terminal session, if I do this: [vagrant@33 ~]$ sudo bash [root@33 vagrant]# which bundle ...
0
votes
2answers
57 views

How to list files and directories of a mount point

Given a mountpoint such as /dev/sda1 how can I list the contents of this file system using shell script. My objective is to delete the oldest file in this drive.
0
votes
2answers
24 views

Number of occurences of letters in a word?

I would like to find out the number of occurrences of each of the alphabets in a word. Eg input aabbbddd output a@2 b@3 c@0 d@3 How can I perform this using shell script?
1
vote
1answer
31 views

Using double or no quotes with wildcards

I came across this article which attempts to explain the find command.It gives an example of find /tmp -iname "data*.txt" now this article here states that Double quotes do not suppress the ...
2
votes
4answers
76 views

unix test when to use eq vs = vs == in test commands?

When should I use -eq vs = vs == e.g. [[ $num -eq 0 ]] [[ $num = 'zzz' ]] I've observed a pattern of using -eq (and -ne, etc.) for numbers and = for strings. Is there a reason for this and ...
3
votes
2answers
86 views

Execute code on remote machine and copy the results back

I'm using some old Fortran code that uses some peculiar memory handling. To make the long story short, it runs on my local machine but fails on the remote one. This is why I would like to ssh to my ...
29
votes
7answers
2k views

Is test or [ or [[ more portable both between bash shells and between other shells?

I see I can do $ [ -w /home/durrantm ] && echo "writable" writable or $ test -w /home/durrantm && echo "writable" writable or $ [[ -w /home/durrantm ]] && echo ...
2
votes
2answers
177 views

Left and right square brackets treated differently by sed/bash

I have a file with the following contents: [root@server list]# cat filenames.txt [AAA','ACMEDEMO2','ACMEDEMO3','ACMEDEMO4','RENTCOGH','TESTENT','DORASINE','LOKAWINK','BBB] [root@qa4app01 list]# I ...
3
votes
2answers
79 views

What is the format for piping a message into sendmail?

I am using the following command to create messages on the fly, and send them: echo "Subject:Hello \n\n I would like to buy a hamburger\n" | sendmail email@example.com It seems that when you send ...
4
votes
1answer
48 views

Are there problems with hyphens in functions, aliases, and executables?

In my testing (in Bash and Z Shell), I saw no problems with defining functions or aliases or executable shell scripts which have hyphens in the name, but I'm not confident that this will be okay in ...
4
votes
3answers
164 views

Change case of n-th letter in a string

I want to change the case of the n-th letter of a string in BASH (or any other *nix tools, e.g. sed, awk, tr, etc). I know that you can change the case a whole string using: ${str,,} # to lowercase ...
1
vote
3answers
102 views

What return/exit values can I use in bash functions/scripts?

I want to know what return values we can use that will not be mistaken by for ex. SIGINT? ex.: $sleep 10 $#hit ctrl+c $echo $? 130 so I know I must not use anything like return 130 or exit 130 so ...
1
vote
3answers
53 views

How to remove matching files from directory A in directory B in the command line?

I have some duplicate files in directories A and B, how could I delete the dupes in B using the filenames from A in bash? How to do it in other shell's is a welcome bonus.
6
votes
3answers
475 views

How do I print '-e' with echo?

I know that echo -e is not an ordinary command. I have tried echo '-e' and echo \-e but they still don`t work.
1
vote
1answer
26 views

RYSNC over SSH not working for restricted shell

I need to give access to some Mr X in my production server so that he can push files to my server. Since there is no necessity to give him shell access , I decided to use restricted shell (rssh) so ...
1
vote
1answer
29 views

How do I get a list of the values of matching attributes using xmllint and xpath?

I'm trying to use xmllint to parse names of Solr cores from the configuration file. This works: xmllint --xpath /solr/cores/core/@name solr.xml |grep -Po '(?<=name=")[a-z-]+(?=")' And it returns ...
2
votes
1answer
45 views

Help with using quotes in grep searches

I have a file with variables in it of the form a(i)%b(j)%c where the a, b, and c are always the same, but the indices i and j may be different (including multiple characters). So I've played around ...
2
votes
2answers
42 views

Adding “ubuntu” user to Vagrant ubuntu instance

I am using a vagrant box : uname -a Linux precise64 3.2.0-23-generic #36-Ubuntu SMP Tue Apr 10 20:39:51 UTC 2012 x86_64 x86_64 It does not have ubuntu user setup , instead it has vagrant one ,so I ...
2
votes
1answer
59 views

GDB cannot exec my test program

My computer run with Ubuntu 14.04. GDB seems to be abnormal in different account. For example I make a very simple test. I write a file under ~/test/test.c like this: #include <stdio.h> ...
0
votes
2answers
71 views

Bash getting integer expression expected

I have following script to check disk usage #!/bin/bash # set alert level 90% is default ALERT=10 OIFS=$IFS IFS=',' storage=$(df -H | grep -vE '^Filesystem|tmpfs|cdrom' | awk '{ print $5 " " ...
4
votes
1answer
95 views

Executing a “fork bomb” safely

We've all seen the "fork bomb" that will render a host non-responsive, even if executed in an unprivileged shell: Warning: Do not execute the following shell script. Just don't. :(){ :|:& };: ...
0
votes
4answers
45 views

Print only directories with more than 31 files

I am using this script to count files on my directory and sub-directories: for i in $(find . -type d) ; do printf "$i %s\t" ; ( find $i -type f | wc -l ) ; done This script works fine. What I ...
2
votes
2answers
43 views

Tar a list of files which don't all exist

I'm running a command from a script like tar -c -f ar.tar a b c d where b, c, and d may not exist, and may be directories. The solutions that I've come up with are piping the output of ls -d to ...
1
vote
1answer
39 views

How portable is this shell assignment?

VAR=${VAR:-value} The purpose is to set the environment variable VAR to value unless it's already set. I see it works in bash and dash, but how portable is it?
3
votes
4answers
210 views

what is the difference between `find .` and /home/user/* as an input to for command

What is the difference between find . and /home/user/* as an input to for command.? For example: for var in $(find .) do echo "$var" done or for var in /home/user/* do echo "$var" done In the ...
2
votes
1answer
28 views

Append same timestamp to multiple filenames

I have several files that I ftp each hour. The receiving system needs to have some sort of identifier that they came from the same batch, so I would like to append a timestamp to the filename. That ...
2
votes
2answers
83 views

Typing text from a shell script [duplicate]

I'm new to shell scripting. I'd like to know if there's a command similar to "echo" for displaying text in a terminal, but instead of simply displaying it immediately, it actually types it, like if ...
0
votes
1answer
16 views

Loop across url with static tokens with Oauth

I need to write a loop where I need to pass a "token" (which is fixed) and a variable (i) in the url. Is there any way I can achieve that? I wrote the following code but it is not working. If I put ...
5
votes
3answers
292 views

How to view last 5 lines from last created/modified file?

Every day I have to take backup and update the status to support teams at particular time for which I need to check last 5 lines of last created/modified *.aff file in a directory and update them. ...
2
votes
2answers
46 views

for loop to iterate through some file nth position

How do I iterate for nth file in a for loop in unix? below some code I have tried but not succeeded #!/bin/bash # n=2 array=( "CTL_MLPOSDTLP1_1.ctl" "CTL_MLPOSDTLP1_2.ctl" "CTL_MLPOSDTLP1_3.ctl" ) ...
0
votes
1answer
34 views

Check for subdirectory

A)I used the following code to get the modified date of a file. But this is also selecting the subdirectories and thus returning an error. How van I fix this. for file in $1/*; do echo `stat ...
1
vote
4answers
126 views

How to subtract two times in shell

I nee to subtract two lines which is in the format of time in shell. Th time format is hh:mm:ss I used the code below to get the time. cat /var/log/kern.log |grep usb |tail -2| awk '{print $3}' The ...
0
votes
1answer
28 views

elif command is throwing error [closed]

Hi is the below elif command correct? elif [[ "${FILECOMMAND}" = "" ] && [[ -f ${ZIPFILE} ]||[ -f ${ZIPFILE3} ]]] I am getting an error when I run it.
0
votes
2answers
41 views

How can I redirect the same message to both stdoud and stderr (without temporary object)

It is easy to redirect stdout or stderr to the same output (file or one of the 2 std output) with a 1>&1,>&2 and/or >file. Is there a way to send the same output to both the std ...
2
votes
2answers
102 views

How to show only total file size of particular extension by `du` command

I have a hundreds of pdf files and html files in a directory. And I want to know total size of pdf files. By command du -ch /var/foo I can see total file size but I only need last line, the total ...
1
vote
1answer
176 views

Adding multiple user with shell script on Ubuntu

Can someone help me in providing me the shell script for creating multiple users on Ubuntu. Password needs to be different for each user. Thanks in advance
1
vote
2answers
43 views

Shell, howto extract letters from $line1=“Test this… test this!”, and print one by one

I am writing a script, which I would like to spice up a bit. What I need, is a loop, which takes one letter at a time, including space, and then write it on the screen, like an old typewriter would ...
2
votes
1answer
52 views

PS1 prompt showing different on local and remote console

This is my PS1 prompt: export PS1="\[\e]0;\u@\h: \w\a\]${debian_chroot:+($debian_chroot)}\[\033[01;35m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ " That shows perfect in remote (SSH) ...
0
votes
1answer
46 views

Why can't my `date` deal with timezones? [duplicate]

I'm having some weird issues with GNU coreutils date v8.4 (CentOS) that aren't occurring in v8.21 (Ubuntu/Mint). On v8.4, I get the following output (I'm in PST): $ date --version | head -n 1 date ...
0
votes
1answer
31 views

Trying to make aliases that open the last modified file

One thing that I frequently do is edit the most recently modified files, so instead of typing "ls -lr" and then "vim lastfile", I thought I would make some shortcuts in my ~/.bash_profile file: alias ...
3
votes
2answers
69 views

Syntax error: word unexpected on io redirection on file descriptor ≥10

I have the following shell script on debian 7: #!/bin/sh case "$IFACE" in lo) # The loopback interface does not count. # only run when some other interface comes up exit ...
0
votes
0answers
19 views

How to check if a shell is interactive or not for Bourne shell [duplicate]

How can I test with a command/condition if I am in an interactive (ran by user) or a batch (ran by a cron job) Bourne shell (not Bash)?
0
votes
1answer
25 views

Pre-process 1 single option

I've got a Shell script (intended for Linux/Mac/Cygwin users) that wraps an executable JAR. Before passing the arguments (long or short form) to the Java program, I need to pre-process one single ...
2
votes
5answers
114 views

How to find different files in UNIX based on . extension?

How to find different files in UNIX based extension. Lets say suppose if I have 100 files for each vamsi.log-vamsi100.log, krishna.txt-krishna100.txt, super.csv..., rajat.jpeg..., ...
0
votes
2answers
76 views

cat STDIN won't work twice in script

I have a script that outputs various information and the text fields of an html form (method POST). When I attempt to cat <&0, it displays properly. However a few lines down, I try to cat ...
1
vote
1answer
36 views

For loop for curling on multiple pages with API's

I am trying to crawl a website for fetching pages using an API. When I issue the command cd desktop/mysite ; curl -O https://api.mysite.com/info?page=2 I get the data on the desktop. Then I wanted ...
1
vote
1answer
52 views

how do I remove ./ from the file name

How do I remove ./ from the file name ./script 1 when entering it as a command. I want to be able to enter the command just as script 1 for it to run?
2
votes
1answer
24 views

`top` not refreshing screen on exit

When I exit top, the prompt reappears at the bottom and I can see the bottom of the last thing it was showing. How can I get top to behave like less i.e. refresh the screen back to when I launched ...