Command Line Tools

convert a video to gif

mkdir frames
ffmpeg -i input -vf scale=320:-1:flags=lanczos,fps=10 frames/ffout%03d.png
convert -loop 0 frames/ffout*.png output.gif
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copy file use ssh

scp -P port /path/to/file username@a:/path/to/destination
scp -P port username@b:/path/to/file /path/to/destination
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terminal startup time

Put
set -x
at the top and
set +x
at the bottom of both files ~/.profile and ~/.bashrc.
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show open ports

netstat -tlp | grep LISTEN
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startup command

/etc/rc.local
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use Vim edit Hex file

• :%!xxd to switch into hex mode
• :%!xxd -r to exit from hex mode

modify a file inside a jar

jar uf jar-file input-file(s)
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make a large file

dd if=/dev/zero of=outputFile bs=2G count=1
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