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Questions tagged [shell-script]

A shell script is a script written for the shell, or command line interpreter, of an operating system.

It is often considered a simple domain-specific programming language. Typical operations performed by shell scripts include file manipulation, program execution, and printing text.

1460 questions
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Batch converting PNG to JPG in linux

Does anyone know a good way to batch-convert a bunch of PNGs into JPGs in linux? (I'm using Ubuntu). A png2jpg binary that I could just drop into a shell script would be ideal.
nedned
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170
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9 answers

looping through `ls` results in bash shell script

Does any one have a template shell script for doing something with ls for a list of directory names and looping through each one and doing something? I'm planning to do ls -1d */ to get the list of directory names.
Daniel A. White
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161
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3 answers

What does export do in BASH?

Possible Duplicate: Difference between “a=b” and “export a=b” in bash It is hard to admit, but I have never really understood what exactly export does to an environment variable. I know that if I don't export a variable I sometimes can't see it…
Chas. Owens
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123
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6 answers

Check if any of the parameters to a bash script match a string

I'm trying to write a script where I want to check if any of the parameters passed to a bash script match a string. The way I have it setup right now is if [ "$3" != "-disCopperBld" -a "$4" != "-disCopperBld" -a "$5" != "-disCopperBld" -a "$6" !=…
iman453
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6 answers

When must I use #!/bin/bash and when #!/bin/sh?

When is #!/bin/bash more appropriate than #!/bin/sh in a shell script?
Hendré
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82
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5 answers

Determine the architecture of a Mac from the command line or script?

I'm writing a shell script, and I need to know the architecture, i.e. PPC or Intel. Back in the day, there was a program /bin/arch that told you, but my Mac doesn't seem to have it. Is there an easy way I can do this? grep for something in a log…
Brian Postow
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82
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15 answers

How to execute .sh files on Windows?

When I am trying to execute a .sh file with the command line ./name.sh, I am getting this error: "." is not recognized as an internal or external command, operable or batch file How can I execute .sh files on Windows?
sushant
78
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11 answers

Log rotation of stdout?

I have a Linux program which can write information to stdout and stderr. I have a shell script which redirects that output to a file in /var/log. (Via >> and 2>&1.) Is there a way to make that log file rotate? (max size, then switch to a different…
Miral
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72
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6 answers

Avoid unwanted path in Zip file

I'm making a shell script to package some files. I'm zipping a directory like this: zip -r /Users/me/development/something/out.zip /Users/me/development/something/folder/ The problem is that the resultant out.zip archive has the entire file path in…
jerwood
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62
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2 answers

What is the difference between set, env, declare and export when setting a variable in a Linux shell?

What is the difference between set, env, declare and export when setting a variable in a Linux shell, such as bash?
user3872279
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53
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3 answers

How to POST file contents using cURL?

I want to do an HTTP POST of the contents (as a string) of a local file located at path/to/my-file.txt to a URL endpoint at http://example.com/. For example, I might want to do the following: Extract the contents of the file my-file.txt as a…
Mowzer
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47
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5 answers

How to test if a variable is equal to a number in shell

I have this shell script that isn't working. Input: Server_Name=1 if [ $Server_Name=1 ]; then echo Server Name is 1 else echo Server Name is not 1 fi Output: Server Name is 1 But, if i change Server_Name=2, the output is: Server Name is…
user2649805
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40
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2 answers

Unix Script: Wait until a file exists

I need a script that will wait for a (examplefile.txt) to appear in the /tmp directory and once it's found to stop the program, otherwise to sleep the file until it's located So far I have: if [ ! -f /tmp/examplefile.txt ] then
Cidricc
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40
votes
2 answers

How can I compare a variable to a text string, rather than integer, in an if/else statement?

In the process of writing a shell script, I ran into an issue with the following if/else statement that falls somewhere in the middle of the script: if [ $act -eq "add" ] then read - "add or update: " $comm git commit -m "$comm $file" else …
tony_perkis666
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40
votes
6 answers

How to extract a complete list of extension types within a directory?

Within a directory, and recursively within it's sub-directories, meaning every directory within a directory is processed, how do I compile a complete list of unique extensions within the directory? OS is Windows XP with all the current updates, but…
blunders
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