Questions about bash only, as opposed to other Bourne/POSIX shells. For all Bourne/POSIX-style shells, use the /shell tag instead.

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1answer
79 views

Bash: Looping through a string

I have a variable Vmac that stores values of multiple MAC addresses, collected from wmic call as follows: Vmac=`wmic --delimiter="," --authentication-file=/path/to/file //IP-ADDR "Select ...
1
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2answers
275 views

How to put $@ in quotes?

My bash script looks like this: #!/bin/bash grep -r --color=always $@ . | nolong The file is saved in /usr/bin/findstr Everything's ok when I run this: findstr hello But when I run this: ...
5
votes
3answers
407 views

Which of the following codes will run in the same process of the current shell

A. { echo "Hello World"; } >outputfile B. ( echo "Hello World" ) >outputfile C. ./anothershell.sh D. /bin/echo "Hello World" Which is right? And what kind of command can run in the same ...
1
vote
4answers
62 views

Delete all files in a directory

I have a directory which includes some files and some folders containing other files. I'm trying to remove these files in the main directory without touching the folders or their contents. I'm using ...
2
votes
1answer
29 views

Copy files that partially matches another files in another location

I have a list of jpeg files in a directory like this (below is just a sample, like the structure is the same but this there are many fo0# sub-folders, not only fo01 and fo01, where each of these ...
1
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1answer
27 views

NginX + PHP-FPM displays blank php pages

I have a problem where my server running NginX with php-fpm loads blank PHP pages (strangely except for my phpinfo.php file, which loads normally). If I put an index.html page in the same directory ...
3
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3answers
119 views

Understanding Bash's Command Substitution

I am trying to understand how exactly Bash treats the following line: $(< $FILE) According to the Bash man page, this is equivalent to: $(cat $FILE) and I can follow the line of reasoning for ...
1
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2answers
41 views

Rename files depending on their parent directory

I have a main directory, let's say main. This main directory has some folders, among which are three folders named ccc ddd and lll, which are the only folders I want to target and work on. Each of ...
1
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1answer
65 views

Environment Variables not getting set in bash_profile

I have my bash_profile environment setting as follows: if [ `hostname` = "devoraebs01" ]; then echo `hostname -f` . /appl_top/deverp/appl/APPSDEVERP_devoraebs01.env When I log into this host, ...
1
vote
1answer
16 views

Awk - matching on 2 columns for differents lines

Given this file: 92157768877;Sof_deme_Fort_Email_am_%yyyy%%mm%%dd%;EMAIL;20/02/2015;1;0;0 92157768877;Sof_trav_Fort_Email_am_%yyyy%%mm%%dd%;EMAIL;20/02/2015;1;0;0 ...
2
votes
2answers
197 views

monitor linux file systems using df

I use df -kh to get the file system usage, but the trouble is if there is any NFS mount failure in any of the boxes the command will hang. Is there a better way to monitor file systems other than df ...
0
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3answers
93 views

How to [constantly] read the last line of a file?

I have client filtering out data from an live MQTT stream which writes the data into a myfile.csv file, here are the last four lines: 1426134425,m,NWRL,MSV,001,d,SVlts,139,1840343,26089,28529,15987 ...
4
votes
2answers
82 views

Replace string in a file with another where both are saved in variables

I want to replace a string found in a file with another string, but both have a special character (in this example it is a . char) e.g 1.0 and 2.0. So this is the command currently used: sed -i ...
0
votes
1answer
14 views

displaying rate information from stream of numbers

Are there any command line tools that would make it easy to display rate information based on a stream of newline separated numbers? For example average "count" per second/minute and total "count" so ...
0
votes
1answer
22 views

Read the last line of tzselect

I am trying to read the result of tzselect into a bash script in order to set the Timezone pragmatically. Code snippet should look like /usr/bin/tzselect #Read last line of tzselect and cp to ...
0
votes
2answers
39 views

Script with multiple arithmetic conditions failing

I'm experiencing problems with a script converting numbers to bytes. If the number is large enough to hit gigabytes or terabytes, the script runs as it should. If the number converts to kilobytes, ...
1
vote
1answer
44 views

Awk sum csv columns based on fields

I have N files like so: file1.txt Header1,Header2,Header3,Header4,Header5 A,B,RANDOM,1,2 C,D,RANDOM,3,4 fileN.txt Header1,Header2,Header3,Header4,Header5 A,B,RANDOM,1,2 C,D,RANDOM,3,4 They all ...
5
votes
4answers
376 views

list graphical processes from terminal

Do no confuse the question here with how to list processes graphically, that is not what I am asking. In the Terminal, how can i see which processes have a GUI? as in things like firefox, vlc, ...
2
votes
2answers
42 views

Is shell parent of all the processes in linux

I have been trying to understand shell scopes and environment in depth. I have been reading about how if we do export VARIABLE=VALUE it will be available in subshell. So I wanted to ask a question I ...
0
votes
1answer
32 views

Bash/OSX script to run commands in 2 Terminal/iTerm tabs?

To run my node server proxy and then my project in Gulp Browsersync, every time i need to run node server in one tab, open a tab in the same directory and run Gulp. I'm not sure if the second tab is ...
0
votes
2answers
61 views

ssh inside a script with 'command' instead of “command”

I am trying to run commands on various nodes of our cluster automatically via a simples script. I have seen that I can run: #!/bin/bash echo "Machine: "$HOSTNAME; ssh machine2 'echo Machine: ...
0
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1answer
16 views

User session connected

When i connect to ssh directly via terminal on unix machine how can i know how many session has been escalated ? i mean Fisrt i connect as root # and su bryan # and su tony # and su emilie # ...
0
votes
1answer
92 views

Linux Bash Script Ideas [closed]

I have been given the task of creating a shell script to show my proficiency in scripting. I am really struggling with ideas on what to do. I would like to create something that is relevant and could ...
1
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4answers
43 views

echo \\* - bash backslash escape behavior, is it evaluated backwards?

So in bash, When I do echo \* * This seems right, as * is escaped and taken literally. But I can't understand that, when I do echo \\* \* I thought the first backslash escaped the second one ...
8
votes
1answer
117 views

Why does brace expansion range use two dots instead of three (ellipsis)?

I finally understood/discovered why I never got to using bash's (and also zsh's) brace expansion range properly: the syntax is {1..10} instead of what I assumed to be an ellipsis, i.e. {1...10}. May ...
-1
votes
1answer
42 views

permission denied on running script despite +x

Script is on exec partition (under /home/~~~ ) and have +x flag (-rwxr-xr-x ). executable on bash shell (not with script) but not on script. script is quite simple. #!/bin/bash data=cat ...
4
votes
3answers
34 views

Can command substitution be nested in variable substitution?

I would like to use variable substitution on a particular string that I access via a command. For example, if I copy something into my clipboard, I can access it like this. $ xclip -o -selection ...
1
vote
1answer
39 views

How to pass a path to a file through a call to perl from bash?

This is a more advanced version of a previous question (How to pass arguments to perl when trying to change a line?) I made. This time I am trying to pass a path, but evertything seems that the the ...
0
votes
1answer
30 views

how to stop at a specific point in a list

I created a shell script called blossom() because my girlfriend's dog Blossom poops and pees on the floor all the time. blossom() { echo poops and pees on floor all the time } Because I am such ...
2
votes
2answers
52 views

Create array in bash with variables as array name

I'm not sure if this has been answered, I've looked and haven't found anything that looks like what I'm trying to do. I have a number of shell scripts that are capable of running against a ksh or ...
4
votes
3answers
216 views

How to read dash files

How can I read a dash file from the terminal other than delimiting it with ./ For example to read a - file we can read it by cat ./-file_name Q: Is there an alternative way to achieve the same ...
0
votes
1answer
75 views

/usr/bin/awk: Argument list too long

I am trying to run the following bash script: #!/bin/bash file=$1 filename=${file%%.*} line1=$(sed -n 1~2p ${file}) seqs=$(grep -v '^>' ${file}) pos=$(echo "${line1}" | awk -F"[__]" ...
2
votes
1answer
70 views

How to add number to awk array elements?

If I have the following bash variable: $ echo "${pos}" 201 719 744 205 354 ...the following produces... !#bin/bash ( IFS=: awk -v str2="$pos" -v sep="[$IFS]" ' BEGIN { ...
3
votes
2answers
160 views

sed command doesn't return what I want

My document doc.lst is compound with numbers and letters like this : 01 ABC and I want to take only the "ABC" part. I tried this, but it includes the numbers in my result.lst. sed -n -e ...
2
votes
1answer
45 views

Push onto array with find exec

I want to iterate over all the files found by find and add each one to an array. Here's what I have so far: myarray=() find . -name '*.php' -exec myarray\+=\({}\) \; echo "${myarray[@]}" Instead, ...
2
votes
1answer
40 views

sanely run all scripts in a directory

i would like to create a shell-script that in turn runs all scripts it finds in a given directory. following restrictions should apply: the scripts ought to be run in alphabetical order ...
0
votes
2answers
38 views

While Read loop to email

I'm having issues with a script i'm writing. I'm trying to monitor free disk space, and to have an email generated for each filesystem over a certain threshold. When using this script with 'echo' ...
1
vote
2answers
43 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 ...
4
votes
5answers
157 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 ...
1
vote
2answers
48 views

Bash: How to create an alias in .bashrc for awk with parameters

I'm trying to add an alias in .bashrc file as follows: ... alias cutf="_cutf" ... _cutf() { awk 'NR >= $2 && NR <= $3 { print }' < $1 } (The function's goal is to show the ...
3
votes
5answers
284 views

How do I loop over output from shuf?

If I do gshuf -e $(seq 1 10) in bash it will print the numbers 1 thru 10 in random order. But if I do: a=$(shuf -e $(seq 1 10)) for i in "${a[@]}" do echo $i echo "next" done It prints ...
1
vote
3answers
37 views

Variable related to variable

I want to get effect like bellow but I do not know how: $> A='/dir' $> B="$A/bin" $> echo $B /dir/bin $> A='/other' $> echo $B /other/bin any ideas?
0
votes
2answers
50 views

linux curl POST request not working

I am trying to make a POST request using curl to retrieve exam results from the page : result odd .... I am using the following syntax but various errors are showing up (like content has moved ...
1
vote
1answer
26 views

What is the proper bash method of prompting the user for administrative password before backing up the usb data to the computer?

mate-terminal --window-with-profile=PROFILENAME="Hold the terminal open" -e "sudo rsync -azvu --log-file=/var/log/simplebackup.log --append-verify --exclude '.gvfs' /media/user/usb/ ...
0
votes
1answer
57 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 ...
0
votes
0answers
53 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 ...
3
votes
2answers
37 views

command substition for multiline output of command?

How can I make the following command substitution work? $ time real 0m0.000s user 0m0.000s sys 0m0.000s $ oldtime="$(time)" bash: command substitution: line 23: syntax error near unexpected ...
2
votes
1answer
46 views

monitor multiple pids with top

I want to monitor memory usage for several processes and came up with a command like this: ps aux |grep -e postgres -e unicorn -e nginx|cut -d' ' -f2|for i in $(xargs); do echo $i; done 16112 16113 ...
1
vote
1answer
43 views

Removing passwords from terminal logs in CentOS 7

Sometimes a user gives a typo when they are trying to give a password after typing a sensitive command, such as su - . The user then will assume they are being given another password request, and ...
-1
votes
1answer
58 views

Linux why do i have to run commands instead of running the bash file [duplicate]

In order to run an executable file, I need to run all the commands in the below bash file first, so I just put those commands in the bash file and run the bash file first, but running the bash file ...