Commands tagged bash (821)

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How to extract 5000 records from each table in MySQL
How to extract data from one table: mysqldump --opt --where="true LIMIT 5000" dbinproduzione tabella > miodbditest_tabella.sql

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Rescan partitions on a SCSI device
Used this after cloning a disk with dd to make the newly written partitions show up in /dev/

Convert encoding of given files from one encoding to another

list block devices
Shows all block devices in a tree with descruptions of what they are.

Upgrade all perl modules via CPAN

Duplicate several drives concurrently
If you have some drive imaging to do, you can boot into any liveCD and use a commodity machine. The drives will be written in parallel. To improve efficiency, specify a larger block size in dd: $dd if=/dev/sda bs=64k | tee >(dd of=/dev/sdb bs=64k) | dd of=/dev/sdc bs=64k To image more drives , insert them as additional arguments to tee: $dd if=/dev/sda | tee >(dd of=/dev/sdb) >(dd of=/dev/sdc) >(dd of=/dev/sdd) | dd of=/dev/sde

renames multiple files that match the pattern
Useful when you want to quickly rename a bunch of files.

Broadcast your shell thru ports 5000, 5001, 5002 ...
run 'nc yourip 5000', 'nc yourip 5001' or 'nc yourip 5002' elsewhere will produce an exact same mirror of your shell. This is handy when you want to show someone else some amazing stuff in your shell without giving them control over it.

Get the full path of a bash script's Git repository head.
Rather than complicated and fragile paths relative to a script like "../../other", this command will retrieve the full path of the file's repository head. Safe with spaces in directory names. Works within a symlinked directory. Broken down: $cd "$(dirname "${BASH_SOURCE[0]}")" temporarily changes directories within this expansion. Double quoted "$(dirname" and ")" with unquoted ${BASH_SOURCE[0]} allows spaces in the path. $git rev-parse --show-toplevel gets the full path of the repository head of the current working directory, which was temporarily changed by the "cd".


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