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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2
votes
1answer
65 views

How to print last login time?

I'd like to know how to set in .bashrc file to print the last login time of users when logging into another user in terminal. I do know that with who or last, but I'd like something a little more ...
7
votes
2answers
407 views

Bash - how to run a command after the previous finished? [duplicate]

Currently I have a script.sh file with the following content: #!/bin/bash wget -q http://exemple.com/page1.php; wget -q http://exemple.com/page2.php; wget -q http://exemple.com/page3.php; I want to ...
2
votes
2answers
167 views

Consecutive commands

Am I correct to assume that when ; joins two commands on a line, Bash always waits until the first command has exited before executing the second command? And similarly, in a shell script containing ...
4
votes
2answers
73 views

How to make program help text automatically pipe through less?

Just now, dpkg --help spit out three pages of output in my face. I was maybe interested in the first ten lines, which show the general usage and most common arguments. I'd like that, whenever I run ...
1
vote
1answer
78 views

bash script problem when run from desktop launcher

I have a script which does the following: Connect via sshfs to a directory on a server Within that directory, there is an encrypted volume. Open it to the device mapper. Mount to a local directory ...
0
votes
1answer
30 views

What does `line 19: 12364 Killed` mean in crontab error message?

I got a daily crontab task: 50 1 * * * sh /my_path/daily_task.sh > /tmp/zen_log 2>&1 This daily_task shell script will run some python scripts and produce a data file. And it fails for ...
1
vote
4answers
75 views

Sort command on more than one field

I have a file with contents 192.168.1.3 192.168.1.4 192.168.1.2 10.1.1.1 10.1.1.2 10.1.1.3 192.168.1.56 192.168.1.43 10.1.1.23 When I gave $ sort -h -t. -k3,4 sort_test.txt 10.1.1.1 10.1.1.2 ...
1
vote
1answer
18 views

Comparing variables in arithmetic

Was wondering if someone can take the time to explain the following: I have a directory of files (PDF), which I place into an array. shopt -s nullglob # Set array ...
1
vote
1answer
58 views

How can subtract 2 floats which have been extracted from 2 other files with BASH [duplicate]

I'm trying to get the difference between two numbers which I have taken from two files. I think my code will make sense: I've tried to make it work by two different methods, didn't work. What I get ...
1
vote
1answer
27 views

Non-block poll from two pipes?

Here is what I want to do.. mkfifo infrequentlog frequentlog sort -m infrequentlog frequentlog > mylog funcA > infrequentlog funcB > frequentlog So that when monitor tail, I can see the ...
1
vote
0answers
32 views

A way to distinguish between interleaved output from two background processes

If I have two backgrounded processes that produce input to STDOUT or STDERR (e.g., two installation scripts), is there an easy way to make these two output streams distinguishable? I guess I can pipe ...
3
votes
2answers
36 views

How can I catch a command exit code for later, in a Makefile?

I have a makefile, with a test suite target, like so: rcheck: foo This shows the output from the foo command on stdout, and returns an exit code from foo which is handled by make as normal. ...
2
votes
1answer
48 views

how can I add an extra character after a word search [closed]

I have the following field names demelog voyapro naisjdf naismc decoide decoccm travide travccm equiccm mariccm Below is a sample of my file. There are more columns before the first fck=83... ...
0
votes
3answers
150 views

Bash ping script file for checking host availability

I am trying to write a bash script in a file that would, when run start pinging a host until it becomes available, when the host becomes reachable it runs a command and stops executing, i tried ...
5
votes
1answer
60 views

Can someone explain how to use flock and file descriptors to lock a file and write to the locked file?

Bare with me as I am new to the flock tool and I haven't used file descriptors as far as I know. I have a bash script that makes a cURL request and writes the output to a file called resp.txt. I ...
2
votes
1answer
48 views

Supply the same filename as argument to two commands [duplicate]

On a git conflict, I can currently do: git diff path/to/some/file.txt ... after reviewing the diff, usually I want to do: git checkout --theirs path/to/some/file.txt && git add ...
1
vote
1answer
62 views

exec redirects in bash

I write a lot of non-interactive scripts where I would like all output to go to a log file and have nothing appear on-screen. To solve this, I've been using: #!/bin/bash exec &> logfile echo ...
3
votes
2answers
102 views

On Ctrl+C, kill the current command but continue executing the script

I have a bash script, wherein I execute a line, sleep for sometime and then tail -f my log file to verify a certain pattern is seen, I press ctrl +c to get out of tail -f and then move to the next ...
0
votes
0answers
31 views

How to use stdout/stderr from multiple program

I'm working with Docker-containers. An important part of Docker is to log error, etc., to stdout/stderr. For example, I want to run the following program by using this command: nginx -g "daemon ...
0
votes
2answers
9 views

Manually executing a CRON - Confused about params

I have this code snippet: $CUSER=tim $APPDIR=/var/www/testing $APPVENV=/var/www/testing/ven cat > $APPDIR/cronfile << EOF PWD=$APPDIR/$CUSER PATH=$APPVENV/bin:\$PATH 0 2 * * * testapp search ...
2
votes
1answer
54 views

Bash Named Pipe - Atomic Reading

I have set up one script to write to a named pipe, then four scripts to read the named pipe. For most of the entries, there are no problems, but when there is little processing to be done on the ...
3
votes
3answers
68 views

Write bash function which operates on list of filenames

I want to define the function cpfromserver in bash so that when I run $ cpfromserver xxx yyy zzz the result is the same as if I had typed $ scp user@remote.server:"/some/location/xxx/xxx.txt ...
2
votes
3answers
64 views

How to insert bash variables in awk?

How to insert bash variables in awk (for example i need to do in in some for loop - like this: in first iteration use awk to search string by first column, next by second column and so on with using ...
1
vote
3answers
145 views

The equivalent of cmd “for” in bash?

I'm a Linux newbie, and I only know little about bash (or any Linux shell - but I just use bash). I'm used to using for %c in (*.*) do {something} in cmd in Windows, and I really feel inconvenient ...
0
votes
2answers
44 views

How to use variables properly in this little script?

Here is a little script to retarget old-wrong symlinks that I want to make interactive. #!/bin/bash # retarget (broken) symbolink links interactively echo -n "Enter the source directory where ...
0
votes
1answer
25 views

Is there a valid way of exporting a variable across different shells?

For some reasons, Im using ksh and zsh in my scripts and returning to -bash, I need to use already set variable values in the spawned shells, writing it to some temp file and using that didn't look ...
6
votes
2answers
386 views

How do I find number of vertical lines available in the terminal?

I'm writing a script which shows the git log for a directory when I cd into it. Such a log can be overwhelming, containing hundreds of lines. So far I have been limiting that to a hard-coded 20 lines ...
0
votes
3answers
66 views

How to run a shell script inside a shell script

I am using bash on Mac OSX. I have a shell file named myshell.sh and I use it to do a lot of things. I have a entrance.sh file which contains: # content of entrance.sh ./myshell.sh arg1 arg2 ...
0
votes
0answers
13 views

how to keep the spaces when inserting line to parameter [duplicate]

When I want to see for example the line number 2 , from the CSV file I get the following line example1 LINE_NUM=2 # sed -n "${LINE_NUM}p" file.csv cwdfwefwe,"aaaaa ","\dsw\dawd\aw ...
3
votes
2answers
163 views

Run crontab only if condition

I have a bash script that emails me whenever a web server is not responding, and the script is ran by cron every 5 minutes. However, if the website goes down for a few hours, I'd receive too many ...
1
vote
1answer
41 views

How to use bash shell for gnuplot to show Greek letter?

I want to write a bash shell for gnuplot to produce figures automatically. But my figure includes Greek letters inside. I have known their ASCII number, how can I show them correctly in figures after ...
0
votes
1answer
32 views

What is the meaning of local[4] in this example

I am looking at this example from the apache spark documentation. It seems to pass a variable called local[4] into the --master variable. I have not seen that before. What does it mean? I am using ...
4
votes
0answers
45 views

Remap Return key in terminal to prevent accidental command on productions servers

I am looking for a way to remap the key for executing commands in terminal (I am using bash) to prevent accidental commands on productions servers. Return should be disabled. I tried the following ...
0
votes
0answers
42 views

Testing outgoing FTP with fake data

I would like to implement a fake FTP transfer in a program I'm working on. Basically I just want there to be FTP traffic happening in the background for a variable length of time. Similar to how iperf ...
1
vote
1answer
43 views

Display result of a command right aligned in terminal

I have a script that goes through many different checks and I use the success, failure functions defined in /etc/init.d/functions to clearly show the action result on the terminal. That works great, ...
2
votes
0answers
36 views

Why is bash -c cutting off the end of my script? [duplicate]

I have a simple script, that is essentially a list of dpkg -i ... commands in a chroot. It looks something like this: chroot /path/to/chroot /bin/bash -e << EOF cd /opt dpkg -i package1_* ...
2
votes
2answers
60 views

Custom bash 'context' when running from FISH

First of all, I'm on OSX10. My default shell is BASH, which I have set up (through .profile and .bashrc) to automatically run the FISH shell when I open my terminal emulator. This allows me to set up ...
1
vote
0answers
31 views

Autocomplete issue in bash with equal sign (=)

I am trying to make autocomplete work and wroted a piece of code to demonstrate an issue I faced up: $ cat completion.sh function _completion_command() { compopt +o bashdefault +o default +o ...
0
votes
3answers
99 views

create XML file using bash script

I want create simple xml file using bash script ( not with dom ) but when I set value in the line then echo print the $lorem word and not the val lorem=LOL echo '<root><foo ...
0
votes
1answer
48 views

Exit /dev/tty after error message

I run this bash function when a button is pressed, it calls my mobile, however when the call ends or I reject the call, it hangs in /dev/tty and does not return to the main program call.sh ...
1
vote
3answers
268 views

How can I pass on parameters 4..99 to another function

I'm calling a function and I want to pass up to 100 paramters onto another function. I do not want to pass on the first 3 params, I start with param4 being the first param for the other program. I ...
1
vote
0answers
42 views

Limit transfer speed rate by Iptables Rules

I have D-Link Router DSL-2730U that support busybox OS and iptables version 1.4.0 I managed successfully to block the host for being connect to the internet using the following command block by ip ...
1
vote
1answer
31 views

Can .bash_profile be auto sourced after change?

I'm always wondering if there's a way to do this. I don't want to type source after changing my .bash_profile all the time.
1
vote
1answer
103 views

grep (/sed/awk) month range

I've looked around for solutions to this, but it's sort of difficult to search for the solution to such a specific problem (lot of words to put in Google). So, I have a file with data that looks like ...
-1
votes
1answer
40 views

Script to `grep` a file with variable [duplicate]

while read wholeline do echo ${wholeline} --outputs John Jones #grab all the lines that begin with these values #grep '^John Jones' workfile2 --works, prints contents of workfile2 where the ...
2
votes
2answers
97 views

How do I have sed only perform actions on the first match?

I have a bash script that extracts headers from the MIME Source of an email. The idea is that I only want to capture the headers of the message nothing else. It's not quite working right though. I ...
0
votes
2answers
35 views

script for substition incremental

I have 4 machines, every machine(centos) has a ifcfg-bond1 with identical ip address 10.0.0.3 How to using bash and sed substituting 10.0.0.3 with a incremental value? I want to obtain something like ...
0
votes
0answers
42 views

Bash - Convert escape character colored text to BBCode

I want to convert a terminal escape-character colored text file to BBCode colored text. For this i've created an Android logfile with logcat -Cd > /sdcard/logcat.txt. The -C switch adds the color ...
0
votes
2answers
43 views

Different PATH formats for .bash_profile [duplicate]

There are few different formats I have seen so far: With quotes and brackets: PATH="/usr/local/bin:${PATH}" With quotes only: PATH="/usr/local/bin:$PATH" None: PATH=/usr/local/bin:$PATH ...
2
votes
1answer
210 views

How to create permanent aliases on Unix-like systems?

I am looking for a simple way to create a permanent alias for all users. So ~/.bashrc or ~/.bash_profile is not an option. Hasn't anybody created a program for this? I think it should be a very ...